Introductory Anatomy of Digestive System

NYUNDO Martin, MD, MMed (Surgeon)LecturerDpt of Surgery and Dpt of Clinical AnatomyFACMED-NUR

General considerations

Digestive system is a series of hollow organs joined in a long, twisting tube from the mouth to the anus and other organs that help the body break down and absorb food

►The main organs are: Mouth and pharynx, Oesophagus Stomach, Small and Large intestines,Appendix and Anus

► Accessory organs: Salivary glands, Liver,

Gallbladder, Pancreas

General considerations cont’d

The gastrointestinal tract has a uniform general histology.The GI tract can be divided into 4 concentric layers:

Mucosa is the innermost layer; this layer comes in direct contact with the food (or bolus), and is responsible for absorption and secretion, important processes in digestion.

Submucosa

Muscularis externa (the external muscle layer)

Adventitia or serosa

Accessory organs:

The liver secretes bile into the small intestine via the bile duct, employing the gallbladder as a reservoir. Apart from storing and concentrating bile, the gallbladder has no other specific function.

The pancreas secretes an isosmotic fluid containing bicarbonate, which helps neutralize the acidic chyme, and several enzymes into the small intestine. Both of these secretory organs aid in digestion

General considerations cont’d

Abdomen

The abdomen is the part of the trunk between the thorax and the pelvis

It is a flexible, dynamic container, housing most of the organs of the digestive system and part of the urogenital system.

Containment of the abdominal organs and their contents is provided by:

musculoaponeurotic walls anterolaterally, diaphragm superiorly, muscles of the pelvis inferiorly, lumbar vertebral column in the posterior.

The abdomen encloses and protects its contents while allowing the flexibility between the more rigid thorax and pelvis required by respiration, posture, and locomotion.

Through voluntary or reflexive contraction, its muscular roof, anterolateral walls, and floor can raise internal (intra-abdominal) pressure to aid expulsion from the abdominopelvic cavity or from the adjacent thoracic cavity, expulsion of air from the thoracic cavity (lungs and bronchi) or of fluid (e.g., urine or vomitus), flatus, feces from the abdominopelvic cavity.

General considerations cont’d

Peritoneum and Peritoneal Cavity

The peritoneum is a continuous, glistening and slippery transparent serous membrane. It lines the abdominopelvic cavity and invests the viscera.

The peritoneum consists of two continuous layers: the parietal peritoneum, which lines the internal surface of the abdominopelvic wall, and the visceral peritoneum, which invests viscera such as the stomach and intestines.

The peritoneal cavity is a potential space of capillary thinness between the parietal and visceral layers of peritoneum.

It contains no organs but contains a thin film of peritoneal fluid, which is composed of water, electrolytes, and other substances derived from interstitial fluid in adjacent tissues.

Peritoneal fluid lubricates the peritoneal surfaces, enabling the viscera to move over each other without friction and allowing the movements of digestion.

In addition to lubricating the surfaces of the viscera, the peritoneal fluid contains leukocytes and antibodies that resist infection.

Lymphatic vessels absorb the peritoneal fluid.

The peritoneal cavity is completely closed in males; however, there is a communication pathway in females to the exterior of the body through the uterine tubes, uterine cavity, and vagina. This communication constitutes a potential pathway of infection from the exterior.

General considerations cont’d

Diaphragm

The diaphragm is a double-domed musculotendinous partition separating the thoracic and abdominal cavities.

Its mainly convex superior surface faces the thoracic cavity, and its concave inferior surface faces the abdominal cavity.

The diaphragm is the chief muscle of inspiration.

It descends during inspiration; however, only its

central part moves because its periphery, as the fixed origin of the muscle, attaches to the inferior margin of the thoracic cage and the superior lumbar vertebrae.

Orifices: vena caval foramen, esophageal hiatus and aortic hiatus.

Esophagus

First part of the digestive tract, that conveys food from the pharynx to the stomach; it is about 25 cm long and 2 cm of diameter.

Is divided into three anatomical parts: cervical (superior), thoracic (middle) and abdominal

(inferior).

The esophagus:

Follows the curve of the vertebral column as it descends through the neck and mediastinum in the median partition of the thoracic cavity.

Has internal circular and external longitudinal layers of muscle.

In its superior third, the external layer consists of voluntary striated muscle; the inferior third is composed of smooth muscle, and the middle third is made up of both types of muscle.

Passes through the esophageal hiatus in the diaphragm,

Terminates by entering the stomach at the cardial orifice of the stomach

Esophagus cont’d

The esophagus has 2 sphincters:

A sphincter is a narrowing caused by contracted (tightened) muscles.

These muscles remain contracted until the body sends a message for the muscles to relax. When the muscles of the sphincter relax, this then allows things to pass.

One sphincter is at the top of the esophagus. The other is where the esophagus meets the stomach this is known as the gastro-esophageal junction.

The lower sphincter controls the movement of food into the stomach and prevents stomach acid from going up into the esophagus (gastro-esophageal reflux).

The lining of the esophagus is very different to that of the stomach and stomach acid will cause it to become inflamed and sore if reflux does occur.

StomachThe stomach is the expanded part of the

alimentary tract between the esophagus and the small intestine.

It is specialized for the accumulation of ingested food, which it chemically and mechanically prepares for digestion and passage into the duodenum.

RESERVOIR

2-3L food in adult 30ml in newborn

SHAPE VARIES

Individual build Respiration Contents Position assumed by individual

Stomach cont’d Parts of the Stomach:

CARDIA the part surrounding the cardial

orifice. Orifice at 7th costal cartilage L 2-4 cm from median; at T10 or T11

level

FUNDUS - the dilated superior part limited inferiorly by the horizontal plane of the cardial orifice.

BODY - the major part of the stomach between the fundus and the pyloric antrum

PYLORUS (Pyloric part) From notch - pyloric sphincter At L1-L3 R median plane

Stomach cont’d

The stomach has two curvatures: Lesser curvature: forms the shorter

concave border of the stomach

Greater curvature: forms the longer convex border of the stomach

Two surfaces: Anterior Posterior

Stomach cont’d

RelationsRelations

FUNDUS – diaphragm

ANT SURFACE - diaphragm, liver L lobe & ant abd wall

POST SURFACE - omental bursa & retroperitoneal structures (kidney, pancreas, spleen.)

SUPERIOR - lesser omentum & gastric vessels.

INFERIOR - greater omentum & gastro-epiploic vessels.

Stomach cont’d

Principles of blood supplyPrinciples of blood supply

2 MAJOR ART SOURCES

Coeliac trunk Superior mesenteric

VENOUS DRAINAGE

Follow arteries

LYMPHATIC DRAINAGE Follow arteries

Stomach cont’d

Venous drainageVenous drainage

FOLLOW ARTS Drain into portal systems R & L → portal vein

R GASTROEPIPLOIC (G-MENTAL) V → superior mesenteric → may enter portal v direct or join splenic v

L GASTROEPIPLOIC (G-MENTAL) → splenic vein and its tributariess & short gastric vs.

Venous drainageVenous drainage

Lymphatic drainageLymphatic drainage

ALL LYMPH PASSES TO COELIAC GP of pre-aortic nodes

ALL LYMPH VS. ACCOMPANY ARTS along the 2 curves

4 MAJOR AREAS OF DRAINAGE

LESSER CURV Largest & drains to L gastric LNs

R PART GREATER CURV Drains gastroepiploic & pyloric LNs

L PART GREATER CURV Drains pyl, gastoepip, & pancreticosplenic LNs

LESSER CURVE RELATED TO PYL Drains to R gastric LNs

LymphaticsLymphatics

Common lymphatics Common lymphatics pathway:pathway:

Drain to coeliac LN → Coeliac trunk →cisterna chyli → Thoracic duct

Nerve supplyNerve supply

PARASYMPATHETIC from ant and post vagal trunks

SYMPATHETIC from coeliac plexus

EFFERENT FIBRES from segments T6-T10

VAGAL TRUNKS Ant → lesser curve→ hepatic & duodenal branch Post → lesser curve from post surface → coeliac →

coeliac plexus → post gastric branch

Nerve supplyNerve supply

3. SMALL INTESTINES

Extent: stomach to colon Length: approximately 5m Parts

Duodenum Jejunum Ileum

DUODENUM

The duodenum, the first and shortest (25 cm) part of the small intestine, is also the widest and most fixed part.

The duodenum pursues a C-shaped course around the head of the pancreas.

The duodenum begins at the pylorus on the right side and ends at the duodenojejunal junction on the left side. ( Treitz ligament)

The junction usually takes the form of an acute angle, the duodenojejunal flexure.

Most of the duodenum is fixed by peritoneum to structures on the posterior abdominal wall and is considered partially retroperitoneal.

The duodenum is divisible into four parts:

Superior (first) part: short (approximately 5 cm) and lies anterolateral to the body of the L1 vertebra.

Descending (second) part: longer (7-10 cm) and descends along the right sides of the L1-L3 vertebrae.

Horizontal (third) part: 6-8 cm long and crosses the L3 vertebra.

Ascending (fourth) part: short (5 cm) and begins at the left of the L3 vertebra and rises superiorly as far as the superior border of the L2 vertebra.

Superior or First Part

Descending orSecond Part

Horizontal or Third Part

Fourth or Ascending Part

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Duodenum blood supply

The arteries arise from the celiac trunk and the superior mesenteric artery. The celiac trunk, via the gastroduodenal artery and its branch,

The veins follow the arteries and drain into the portal vein, some directly and others indirectly, through the superior mesenteric and splenic veins.

The lymphatic vessels of the duodenum follow the arteries.

CLINICALCORRELATES Duodenal ulcer

Usual located sup aspect - 1st part

When post, penetration may cause bleeding (gastroduodenal art) or erosion into head of pancreas

Ant ulcers may perforate into peritoneum (peritonitis).

JEJUNUM & ILEUM Jejunum: 2nd part of the small intestine, begins at the duodenojejunal

flexure at the Treitz ligament where the alimentary tract resumes an intraperitoneal course.

Wider, thicker-walled than ileum Mucous membrane thrown into circular folds with many longer villi

Ileum: third part of the small intestine, ends at the ileocecal junction, the union of the terminal ileum and the cecum .

Together, the jejunum and ileum are 6 to 7 m long, the jejunum constituting approximately two fifths and the ileum approximately three fifths of the intraperitoneal section of the small intestine.

Jejunum and ileum

Although no clear line of demarcation between the jejunum and ileum exists, they have distinctive characteristics that are surgically important

The jejunum and ileum can be distinguished by ther color, feel and their complexity of arterial arcades:

♦ Jejum: redder wall, thicker wall(feels full) and simple arcades

♦ Ileum: thinner wall, (feels empty), multiple arcades

The mesentery is a fan-shaped fold of peritoneum that attaches the jejunum and ileum to the posterior abdominal wall

The superior mesenteric artery supplies the jejunum and ileum .

The superior mesenteric vein drains the jejunum and ileum.

Specialized lymphatic vessels in the intestinal villi

Blood vs. arrangement varies jej & ileum

MESENTERIC LYMPH NODES

Large Intestine

The large intestine is the site where water is absorbed from the indigestible residues of the liquid chyme, converting it into semisolid stool or feces that is stored temporarily and allowed to accumulate until defecation occurs.

Extent Ileocaecal junction to anus; about 1.5 m long

Parts: Caecum & vermiform appendix Ascending, transverse & descending Sigmoid Rectum & anal canal

Small & large intestines

Large Intestine cont’d

The large intestine can be distinguished from the small intestine by: Omental appendices: small, fatty, omentum-like

projections. Three teniae coli:

(1) mesocolic, to which the transverse and sigmoid mesocolons attach;

(2) omental, to which the omental appendices attach; and (3) free (L. libera), to which neither mesocolons nor

omental appendices are attached. Haustra: sacculations of the wall of the colon between

the teniae A much greater caliber (internal diameter). Mucosa

No villi, numerous mucus cells

Caecum

Blind sac invested in peritoneum 8 cm W x 8 cm L, located in RIF

Vermiform appendix Attached to posteromedial wall Taenia coli converge on appendix

Ileocaecal orifice Opens on medial wall Surrounded by ileocaecal sphincter

Caecum & vermiform appendix

Vermiform appendix

About 8 cm long Arises posteromedial aspect of caecum

About 3 cm below ileocaecal orifice Mesoappendix

Connects perit. to ileum Appendicular art within this fold

Commonly behind caecum or in pelvis Very mobile & its relations are variable

Position of the Appendix

A retrocecal appendix extends superiorly toward the right colic flexure and is usually free.

The appendix may project inferiorly toward or across the pelvic brim.

The anatomical position of the appendix determines the symptoms and the site of muscular spasm and tenderness when the appendix is inflamed.

The base of the appendix lies deep to a point that is one third of the way along the oblique line joining the right ASIS to the umbilicus (the McBuney point on the spinoumbilical line).

Ascending colon

Lies R lateral flank

Extent Iliocaecal orifice to R colic flexure 15 cm long

Peritoneum Cover ant & both sides, fixing it to post wall

Relations of ascending colon

Post Lower pole R kidney Iliohypogastric & ilioinguinal nerves

Ant Coils of small intestines Parts of greater omentum

Transverse colon

50 cm long At umbilicus level; largest & most mobile

Extent R - L colic flexures across the abd L flexure more superior, acute angle & less

mobile than R flexure

Sup: transverse mesocolon suspends it Inf: mesentery loops down to iliac crest,

adherent to post wall of omental bursa

Transverse colon

Relations of the transverse colon

Post R-L 2nd part duodenum, head of pancreas,

small intestine, L kidney Anterosuperiorly R-L

Liver, gb, stomach, greater omentum & spleen

Transv colon mesentery Attaches to body of pancreas Continuous with parietal peritoneum

Descending colon

Narrowest part of colon; L lateral flank Extent: Splenic flexure-LIF 30 cm long Peritoneum cover ant & on both sides,

fixing it to post wall Flexure attached to diaphragm by

phrenico-colic ligament, that also supports the spleen

Relations of descending colon

Post Lower pole L kidney & diaphragm Quadratus lumborum, iliacus & psoas

Peritoneal surfaces In contact with coils of small intestines

Sigmoid colon

LIF, pelvic brim - S3 ant 40 cm long, varies in position Attached to pelvic wall by an inverted V-

shaped sigmoid mesentery Apex of V overlies L ureter, at bifurcation

of common iliac v & L sacroiliac joint Taenia coli terminate 15 cm from anus,

marking the recto-sigmoid junction

Relations of sigmoid colon

Post Lies on L ureter & common iliac vessels

Sup Covered by coils of small intestine

Inf Lies on urinary bladder in male Lies on uterus in female

Rectum

12 cm long, pelvic & no mesentery

Extent

Rectosigmoid (S3) - anorectal j Course: from S3 curves forward, loops

L as far as coccyx tip; widens inf. into a rectal ampulla

Relations of the rectum

Lat: coils of small int covered by peritoneum Inf: levator ani, coccyx & rectal vs Post: sup rectal art, S3, S4 & S5, symp

trunk, lat & median sacral vs lower part of sacrum, coccyx

In both sexes, upper ⅓ forms post wall of rectovesical pouch in ♂,& rectouterine in ♀

In ♂: sem vesicles, d deferens, bladder & prostate; in ♀ post wall vagina & uterus

Anal canal

4 cm long External & internal sphincters Internal

Involuntary (circular muscle coat) Upper 2/3 canal, innervated by pelvic

plexus; sympathetic stimulation contracts muscle

Anal canal - cont…

External - lower ⅓ of canal Superficial - surrounds lower part;

attaches to anococcygeal body & perineal body; inf. rectal n

Deep - mid part of canal, levator ani reinforces & essential in function

Subcutaneous - thick ring of muscle surrounding anal orifice

Blood supply of large intestine

Clinical correlates

Appendicitis Cancer of large intestines

ACCESORY ORGANES

Spleen

The spleen is an ovoid organ; varies considerably in size, weight, and shape; however, it is usually approximately 12 cm long and 7 cm wide.

The spleen is located in the left upper abdominal quadrant or hypochondrium, where it receives the protection of the lower thoracic cage

The diaphragmatic surface of the spleen is convexly curved to fit the concavity of the diaphragm.

The anterior and superior borders of the spleen are sharp and often notched, whereas its posterior (medial) end and inferior border are rounded.

It is relatively delicate and considered the most vulnerable abdominal organ.

As the largest of the lymphatic organs, it

participates in the body's defense system as a site of lymphocyte (white blood cell) proliferation and of immune surveillance and response.

The relations of the spleen are

Anteriorly, the stomach. Posteriorly, the left part of the diaphragm, Inferiorly, the left colic flexure. Medially, the left kidney.

The spleen contacts the posterior wall of the stomach and is connected to its greater curvature by the gastrosplenic ligament and to the left kidney by the splenorenal ligament.

These ligaments, containing splenic vessels, are attached to the hilum of the spleen on its medial aspect .

The splenic hilum is often in contact with the tail of the pancreas and constitutes the left boundary of the omental bursa.

Splenic vessels

The splenic artery is the largest branch of the celiac trunk Between the layers of the splenorenal ligament, the splenic artery divides into five or more branches that enter the hilum.

The splenic vein is formed by several tributaries that emerge from the hilum. With the IMV and SMV form the portal vein.

The splenic lymphatic vessels leave the lymph nodes in the splenic hilum and pass along the splenic vessels to the pancreaticosplenic lymph nodes

The nerves of the spleen, derived from the celiac nerve plexus, are distributed mainly along branches of the splenic artery, and are vasomotor in function

Pancreas

The pancreas is an elongated, accessory digestive gland that lies retroperitoneally and transversely across the posterior abdominal wall, posterior to the stomach between the duodenum on the right and the spleen on the left.

The pancreas produces

An exocrine secretion (pancreatic juice from the acinar cells) that enters the duodenum through the main and accessory pancreatic ducts.

Endocrine secretions (glucagon and insulin from the pancreatic islets [of Langerhans]) that enter the blood.

The pancreas is divided into four parts: head, neck, body, and tail.

The head of the pancreas is the expanded part of the gland that is embraced by the C-shaped curve of the duodenum to the right of the superior mesenteric vessels.

Pancreatic ducts

The main pancreatic duct begins in the tail of the pancreas and runs through the parenchyma of the gland to the pancreatic head: here it turns inferiorly and is closely related to the bile duct.

Most of the time, the main pancreatic duct and the bile duct unite to form the short, dilated hepatopancreatic ampulla (of Vater), which opens into the descending part of the duodenum at the summit of the major duodenal papilla.

The sphincter of the pancreatic duct (around the terminal part of the pancreatic duct), the sphincter of the bile duct (around the termination of the bile duct), and the hepatopancreatic sphincter (of Oddi); around the hepatopancreatic ampulla are smooth muscle sphincters that control the flow of bile and pancreatic juice into the duodenum.

BLOOD SUPPLY OF PANCREAS

The pancreatic arteries derive mainly from the branches of the markedly tortuous splenic artery, which form several arcades with pancreatic branches of the gastroduodenal and superior mesenteric arteries.

The corresponding pancreatic veins are

tributaries of the splenic and superior mesenteric parts of the portal vein; however, most of them empty into the splenic vein.

The pancreatic lymphatic vessels follow the blood vessels.

Most vessels end in the pancreaticosplenic lymph nodes, that lie along the splenic artery. Some vessels end in the pyloric lymph nodes.

The nerves of the pancreas are derived from the vagus and abdominopelvic splanchnic nerves passing through the diaphragm.

The parasympathetic and sympathetic fibers reach the pancreas by passing along the arteries from the celiac plexus and superior mesenteric plexus

LIVER

The liver is the largest gland. It weighs approximately 1500 g and accounts for approximately 2.5% of adult body weight.

It extends into the left hypochondrium, inferior to the

diaphragm.

Except for fat, all nutrients absorbed from the gastrointestinal tract are initially conveyed first to the liver by the portal venous system.

In addition to its many metabolic activities, the liver stores glycogen and secretes bile.

Bile passes from the liver via the biliary ducts;right and left hepatic ducts that join to form the common hepatic duct, which unites with the cystic duct to form the bile duct.

The liver produces bile continuously; however, between meals it accumulates and is stored in the gallbladder, which also concentrates the bile by absorbing water and salts. When food arrives in the duodenum, the gallbladder sends concentrated bile through the bile ducts to the duodenum.

Surfaces, Peritoneal Reflections, and Relationships of the Liver

The liver has a convex diaphragmatic surface (anterior, superior, and some posterior) and a relatively flat or even concave visceral surface (posteroinferior),

Anatomical Lobes of the Liver

Externally, the liver is divided into two lobes and two accessory lobes by the reflections of peritoneum from its surface.

The essentially midline plane defined by the attachment of the falciform ligament and the left sagittal fissure separates a large right lobe from a much smaller left lobe

Biliary Ducts and Gallbladder

The biliary ducts convey bile from the liver to the duodenum.

Bile is produced continuously by the liver and stored and concentrated in the gallbladder, which releases it intermittently when fat enters the duodenum. Bile emulsifies the fat, so that it can be absorbed in the distal intestine.

Bile Duct

The bile duct (formerly, common bile duct) forms in the free edge of the lesser omentum by the union of the cystic duct and the common hepatic duct. The length of the bile duct varies from 5 to 15 cm, depending on where the cystic duct joins the common hepatic duct.

Gallbladder

The gallbladder (7-10 cm long) lies in the fossa for the gallbladder on the visceral surface of the liver.

The pear-shaped gallbladder can hold up to 50 mL of bile. Peritoneum completely surrounds the fundus of the gallbladder and binds its body and neck to the liver.

The hepatic surface of the gallbladder attaches to the liver by connective tissue of the fibrous capsule of the liver.

The gallbladder has three parts: Fundus: the wide end of the organ, projects

from the inferior border of the liver and is usually located at the tip of the right 9th costal cartilage in the MCL.

Body: contacts the visceral surface of the liver, the transverse colon, and the superior part of the duodenum.

Neck: narrow and tapered; directed toward the porta hepatis; it makes an S-shaped bend and joins the cystic duct.

The cystic duct (3-4 cm long) connects the neck of the gallbladder to the common hepatic duct.

The cystic duct passes between the layers of the lesser omentum, usually parallel to the common hepatic duct, which it joins to form the bile duct.

Introductory Anatomy of Respiratory System

NYUNDO Martin, MD,MMed (General Surgeon)LecturerDpt of Surgery and Dpt of Clinical AnatomyFACMED-NUR

General considerations

The respiratory system is made up of the organs involved in respiration

Respiration is the act of breathing

inhaling (inspiration) - taking in oxygen exhaling (expiration) - giving off carbon dioxide

The respiratory system consists of the: Nose, pharynx, larynx, trachea, bronchi and lungs

lungs

The pleura and airways

The respiratory tract is most often discussed in terms of

upper and lower parts.

The upper respiratory tract relates to the nasopharynx and larynx whereas the lower relates to the trachea, bronchi and lungs.

Beginning at the larynx, the walls of the airway are supported by C-shaped rings of hyaline cartilage.

The sub-laryngeal airway constitutes the

tracheobronchial tree.

The thorax includes the primary organs of the respiratory and cardiovascular systems

The thorax is the superior part of the trunk between the neck and abdomen

Commonly the term chest is used as a synonym for thorax

The thoracic cavity is divided into three major spaces:

The central compartment, or mediastinum, houses the conducting structures that make up the thoracic viscera, except for the lungs

The lungs occupy the lateral compartments or pulmonary cavities that lie on each side of the mediastinum. Thus the majority of the thoracic cavity is occupied by the lungs,

Parts of Respiratory system

Pharynx, Larynx

Trachea

Bronchi

Lungs

The trachea

Located within the superior mediastinum, constitutes the trunk of the tree

It bifurcates at the level of the transverse thoracic

plane (or sternal angle) into main (primary) bronchi, one to each lung, passing inferolaterally to enter the lungs at the hila (hilum)

The trachea 2

Course

the trachea commences at the level of the cricoid cartilage in

the neck (C6) It terminates at the level of the angle of Louis (T4/5) where it

bifurcates into right and left main bronchi

Structure

The trachea is a rigid fibroelastic structure Incomplete rings of hyaline cartilage continuously maintain the

patency of the lumen. The trachea is lined internally with ciliated columnar

epithelium.

Trachea3

Relations

Behind the trachea lies the oesophagus The 2nd, 3rd and 4th tracheal rings are crossed

anteriorly by the thyroid isthmus

Blood supply

the inferior thyroid bronchial arteries

Bronchi

The right main bronchus is shorter, wider and takes a more vertical course than the left

The width and vertical course of the right main bronchus account

for the tendency for inhaled foreign bodies to preferentially impact in the right middle and lower lobe bronchi.

The left main bronchus enters the hilum and divides into a superior and inferior lobar bronchus

The right main bronchus gives off the bronchus to the upper lobe prior to entering the hilum and once into the hilum divides into middle and inferior lobar bronchi.

the air: enters the body through the nose or the mouth travels down the throat through the larynx (voice box) and

trachea (windpipe) goes into the lungs through tubes called main-stem bronchi one main-stem bronchus leads to the right lung and one to the left

lung in the lungs, the main-stem bronchi divide into smaller bronchi and then into even smaller tubes called bronchioles bronchioles end in tiny air sacs called alveoli

The bronchi and bronchopulmonary segments

Each lobar bronchus divides within the lobe into segmental bronchi

Each segmental bronchus enters a bronchopulmonary segment

Each bronchopulmonary segment is pyramidal in shape with its apex directed towards the hilum

It is a structural unit of a lobe that has its own segmental

bronchus, artery and lymphatics.

Beyond the direct branches of the lobar bronchi that is, beyond the segmental bronchi are from 20 to 25 generations of branches that eventually end in terminal bronchioles

Each terminal bronchiole gives rise to several

generations of respiratory bronchioles,

Each respiratory bronchiole provides 2-11 alveolar ducts,

Each of which gives rise to 5-6 alveolar sacs lined by alveoli.

The pulmonary alveolus is the basic structural unit of gas exchange in the lung.

New alveoli continue to develop until about age 8 years, by which time there are approximately 300 million alveoli.

LUNGS

The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue.

Function

What do lungs do?

The lungs are the vital organs of respiration Their main function is to oxygenate the blood by

bringing inspired air into close relation with the venous blood in the pulmonary capillaries

The lungs take in oxygen, which all cells throughout the body need to live and carry out their normal functions

The lungs also get rid of carbon dioxide, a waste product of the body's cells.

The lungs are separated from each other by the mediastinum, an area that contains the following:

heart and its large vessels trachea (windpipe) esophagus lymph nodes

The lungs are inside in a membrane called the pleura.

The pleural cavity:”the potential space between the layers of pleura ”contains a capillary layer of serous pleural fluid, which lubricates the pleural surfaces and allows the layers of pleura to slide smoothly over each other during respiration.

Its surface tension also provides the cohesion that keeps the lung surface in contact with the thoracic wall; consequently, the lung expands and fills with air when the thorax expands while still allowing sliding to occur, much like a layer of water between two glass plates.

Description of the lungs:

Lobes marked by fissures:

The right lung has three lobes The left lung has two lobes.

Apex

Basis (diaphragmaic surf)

Border (ant, post and inf)

Surfaces ( costal, mediastinal and diaphragmatic)

Relations of the lungs Heart Thoracic Aorta Esophagus Pulmonary artery Pulmonary veins Sup and inf vena cava

CLINICAL CORRELATES

Infections: bronchitis

Pneumothorax: Entry of air into the pleural cavity, resulting from a penetrating

wound of the parietal pleura Fractured ribs may also tear the visceral pleura and lung, thus

producing pneumothorax.

Hydrothorax : The accumulation of a significant amount of fluid in the pleural cavity may result from pleural effusion (escape of fluid into the pleural cavity).

Hemothorax

With a chest wound, blood may also enter the pleural cavity.

Hemothorax results more commonly from injury to a major intercostal or internal thoracic vessel than from laceration of a lung.

Hemopneumothorax : If both air and fluid, (if the fluid is blood) accumulate in

the pleural cavity, an air fluid level or interface (sharp line, horizontal regardless of the patient's position, indicating the upper surface of the fluid) will be seen on a radiograph.

Thoracentesis:

Sometimes it is necessary to insert a hypodermic needle through an intercostal space into the pleural cavity to obtain a sample of fluid or to remove blood or pus .

To avoid damage to the intercostal nerve and vessels, the needle is inserted superior to the rib, high enough to avoid the collateral branches.

Thoracic drainage: chest tube

LUNG CANCER

Lung cancer usually starts in the lining of the bronchi, but can also begin in other areas of the respiratory system, including the trachea, bronchioles, or alveoli.

Lung cancers are believed to develop over a period of many years

Nearly all lung cancers are carcinomas, a cancer that begins in the lining or covering tissues of an organ.

What are the risk factors for lung cancer?

A risk factor is anything that increases a person's chance of getting a disease such as cancer

Different cancers have different risk factors. Several risk factors make a person more likely to develop lung cancer:

Smoking is the leading cause of lung cancer, with more than 90 percent of lung cancers thought to be a result of smoking.

Additional risk factors include:

second-hand smoke - breathing in the smoke of others. .

Introductory Anatomy of Urinary System

NYUNDO Martin, MD, MMed (Surgeon)LecturerDpt of Surgery and Dpt of Clinical AnatomyFACMED-NUR

General considerations

The urinary system, with other organs regulates the volume and composition of the interstitial fluid.

The urinary system consists of the following organs:

Two kidneys, a single, midline urinary bladder, two ureters, which carry urine from the kidneys to

the urinary bladder a single urethra, which carries urine from the

bladder to the outside of the body

KIDNEYS

The kidneys are the major excretory organs of the body;

they remove most waste products, many of which are toxic, from the blood and play a major role in controlling blood volume, the concetration of ions in the blood, the pH of the blood, red blood cell production and vitamin D metabolism.

The skin, liver, lungs and intestines eliminate some waste products, but if kidneys fail to function, other excretory organs cannot adequately compensate.

KIDNEYS

The kidneys are bean shaped purplish-brown organs located below the ribs toward the middle of the back.

The lie on the posterior abdominal wall behind the peritoneum

The superior pole of each kidney is protected by the rib cage, and the right kidney is slightly lower than the left because of the presence of the liver superior to it.

Each kidney measures about 11cm long, 5 cm wide and 3cm thick and weighs about 130g

On the medial side of each kidney is a small area called the hilium, where the renal artery and nerves enter and the renal vein and the ureter exit

The hilium opens into a cavity called the renal sinus which contains fat and connective tissue

The kidney is divided into an outer cortex and an inner medulla that surrounds the renal sinus

The medulla cosists of a number of cone shaped, renal pyramids, which appear triangular when seen in a longitudinal section of the kidney

The base of each pyramid is located at the boundary between the cortex and the medulla, and the tips of the pyramids, the renal papillae are pointed toward the center of the kidney.

Funnel shaped structures called minor calyces surround the renal papillae

The minor calyces from several pyramids join together to form larger funnels called major calyces

There are 8 to 20 minor calyces and 2 or 3 major calyces per kidney

This major calyces converge to form an anlarged channel called the renal pelvis, which is located in the renal sinus

The renal pelvis then narrows to form a small tube, the ureter which exits the kidney and connects to the urinary bladder

Urine formed within the pyramids passes from the renal papillae into the minor calyces, from there urine moves into the the major calyces, collects in the renal pelvis and exits the kidney through the ureter.

Nephron The basic histological and functional unit of the kidney is

the nephron, which consists of an enlarged terminal

end called Bowman’s capsule, a proximal convuluted tubule, a loop of Henle and distal convuluted tubule.

The distal convuluted tubule empties into a collecting duct, which carries the urine from the cortex of the kidney to the calyces.

The Bowman’s capsule and both convoluted tubules are in the renal cortex

The collecting tubules and parts of the loops of Henle enter the renal medulla.

There are about 1.300.000 nephrons in each kidney and one third of them must be functional to ensure survival.

BLOOD SUPPLY

Renal artery from the abdominal aorta

Renal vein exits the kidney and connects to the inferior vena cava

Ureters and urinary bladder

Ureters

narrow tubes that carry urine from the kidneys to the bladder.

The ureters extend inferiorly and medially from the renal pelvis at the renal hilium to reach the urinary bladder.

Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys.

If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

The urinary bladder

is a hollow muscular container that lies in the pelvic cavity just posterior to the symphysis pubis.

In male it is just anterior to the rectum and in the female it is just anterior to the vagina znd inferior and anterior to the uterus.

The size of the bladder depens on the presence or absence of the urine.

The ureters enter the bladder inferiorly on its posterolateral surface, and the urethra exits the bladder inferiorly and anteriorly

The traingular area of the bladder wall between the two ureters posteriorly and the urethra anteriorly is called trigone; this region differs histologically from the rest of the bladder wall and does not expand during bladder filling

At the junction of the urethra with the bladder, smooth muscle of the bladder forms the internal urinary sphincter

The external urinary sphincter is skeletal muscle that surrounds the the urethra as the urethra extends through the pelvic floor

The sphincters control the flow of urine through the urethra.

In the male the urethra extends to the end of the penis, where it opens to the outside

The female urethra is much shorter than the male urethra and opens into the vestibule anterior to the vaginal opening

Facts about urine

Adults pass about a quart and a half of urine each day, depending on the fluids and foods consumed.

The volume of urine formed at night is about half that formed in the daytime.

Normal urine is sterile. It contains fluids, salts and waste products, but it is free of bacteria, viruses and fungi.

The tissues of the bladder are isolated from urine and toxic substances by a coating that discourages bacteria from attaching and growing on the bladder wall

Introductory Anatomy of Reproductive System

NYUNDO Martin, MD, MMed (Surgeon)LecturerDpt of Surgery and Dpt of Clinical AnatomyFACMED-NUR

Animals’ reproductive systems can be divided into the internal reproductive organs and the external genitalia. The gonads are the actual organs that produce the gametes. In the male, testes (singular = testis) produce sperm cells, and in the female, ovaries make ovules (eggs).

Male Reproductive System

Testis . Sperm cells are produced in the testes located

in the scrotum. Normal body temperature is too hot thus is lethal to sperm so the testes are outside of the abdominal cavity where the temperature is about 2° C (3.6° F) lower..

Epididymis From there, sperm are transferred to the, coiled

tubules also found within the scrotum, that store sperm and are the site of their final maturation.

Vas deferens (plural = vasa deferentia) In ejaculation, sperm are forced up int the

vas deferens From the epididymis, the vas deferens goes up, around the front of, over the top of, and behind the bladder.

The ends of the vasa deferentia, behind and slightly under the bladder, are called the ejaculatory ducts.

The seminal vesicles are also located behind

the bladder. Their secretions are about 60% of the total volume of the semen (= sperm and associated fluid) and contain mucus, amino acids, fructose as the main energy source for the sperm, and prostaglandins to stimulate female uterine contractions to move the semen up into the uterus.

The seminal vesicles empty into the ejaculatory ducts. The ejaculatory ducts then empty into the urethra (which, in males, also empties the urinary bladder).

PROSTATE The initial segment of the urethra is surrounded by

the prostate gland (note spelling!). The prostate is the largest of the accessory glands and puts its secretions directly into the urethra. These secretions are alkaline to buffer any residual urine, which tends to be acidic, and the acidity of the woman’s vagina.

The prostate needs a lot of zinc to function properly, and insufficient dietary zinc (as well as other causes) can lead to enlargement which potentially can constrict the urethra to the point of interferring with urination.

The bulbourethral glands or Cowper’s glands are the third of the accessory structures. These are a small pair of glands along the urethra below the prostate. Their fluid is secreted just before emission of the semen, thus it is thought that this fluid may serve as a lubricant for inserting the penis into the vagina, but because the volume of these secretions is very small, people are not totally sure of this function.

Penis

The urethra goes through the penis.

In humans, the penis contains three cylinders of spongy, erectile tissue (corpus cavemosum and corpus spongiosum) . During arousal, these become filled with blood from the arteries that supply them and the pressure seals off the veins that drain these areas causing an erection, which is necessary for insertion of the penis into the woman’s vagina.

The head of the penis, the glans penis, is very sensitive to stimulation.

In humans, as in other mammals, the glans is covered by the foreskin or prepuce, which may have been removed by circumcision.

Female Reproductive System

Ovary ovules are produced in the ovaries, Each ovule is released into the abdominal

cavity near the opening of one of the oviducts or Fallopian tubes.

Uterus

The uterus is a hollow, thick-walled, pear-shaped muscular organ in the female reproductive system.

During pregnancy the uterus expands to accommodate a developing embryo.

It is located between the urinary bladder in front and the rectum behind, and sits above the vagina.

The lower narrow portion of the uterus is called the cervix and it protrudes downward into the opening of the vaginal canal.

The vaginal canal extends downward to the external female genitalia.

The uterine tubes, or Fallopian tubes, extend from either side of the uterus and act as a channel for eggs from the ovary to travel to the uterus. When an egg is fertilized (joined with sperm), it becomes embedded in the wall of the uterus (whose lining becomes thickened) where the fertilized egg grows into an embryo and later a fetus.

If an egg is not fertilized, the thickened uterine lining sloughs off in a process known as menstruation.

The uterus has thick, muscular walls and is very small.

In a nulliparous woman, the uterus is only about 7 cm long by 4 to 5 cm wide, but it can expand to hold a 4 kg baby.

The lining of the uterus is called the endometrium, and has a rich capillary supply to bring food to any embryo that might implant there.

Vagina

The vagina is a relatively-thin-walled chamber It servs as a repository for sperm (it is where the penis is

inserted), and also serves as the birth canal. Note that, unlike the male, the female has separate opening for the urinary tract and reproductive system.

These openings are covered externally by two sets of skin folds. The thinner, inner folds are the labia minora and the thicker, outer ones are the labia majora.

The labia minora contain erectile tissue like that in the penis, thus change shape when the woman is sexually aroused.

The opening around the genital area is called the vestibule. There is a membrane called the hymen that partially covers the

opening of the vagina. This is torn by the woman’s first sexual intercourse (or sometimes other causes like injury or some kinds of vigorous physical activity).

In women, the openings of the vagina and urethra are susceptible to bacterial infections if fecal bacteria are wiped towards them. Thus, while parents who are toilet-training a toddler usually wipe her from back to front, thus “imprinting” that sensation as feeling “right” to her, it is important, rather, that that little girls be taught to wipe themselves from the front to the back to help prevent vaginal and bladder infections. Older girls and women who were taught the wrong way need to make a conscious effort to change their habits.

At the anterior end of the labia, under the pubic bone, is the clitoris, the female equivalent of the penis. This small structure contains erectile tissue and many nerve endings in a sensitive glans within a prepuce which totally encloses the glans.

This is the most sensitive point for female sexual stimulation, so senstiive that vigorous, direct stimulation does not feel good.