Anatomy & Physiology IChapter 1

Anatomy: The study of form (structure) Subdivisions:

Gross Anatomy - study of structures that can be seen with the naked eyeNeuroanatomy – study of nervous system structureMicroscopic Anatomy – study of structures that are too small to see with the naked eye

Cytology – study of cellsHistology – study of tissues

Physiology: The study of function at many levels

Subdivisions are based on organ systems neurophysiology (physiology of nervous system)endocrinology (physiology of hormones)pathophysiology (mechanisms of disease)

The Human Body

All living things are organized.

AtomsMoleculesOrganellesCellsTissue Organ Organ System Organism

MoleculeAtoms

Chemical levelAtoms combine to form molecules.1

OrganelleMoleculeAtoms

Chemical levelAtoms combine to form molecules.

Cellular levelCells are made up ofmolecules.

Smooth muscle cell

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OrganelleMoleculeAtoms

Chemical levelAtoms combine to form molecules.

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist of similartypes of cells.

Smooth muscle cell

Smooth muscle tissue

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3

OrganelleMoleculeAtoms

Chemical levelAtoms combine to form molecules.

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist of similartypes of cells.

Organ levelOrgans are made up of different typesof tissues.

Smooth muscle cell

Smooth muscle tissue

Connective tissue

Blood vessel (organ)

Epithelialtissue

Smooth muscle tissue

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Cardiovascularsystem

OrganelleMoleculeAtoms

Chemical levelAtoms combine to form molecules.

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist of similartypes of cells.

Organ levelOrgans are made up of different typesof tissues.

Organ system levelOrgan systems consist of differentorgans that work together closely.

Smooth muscle cell

Smooth muscle tissue

Connective tissue

Blood vessel (organ)

HeartBloodvessels

Epithelialtissue

Smooth muscle tissue

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3

4

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Cardiovascularsystem

OrganelleMoleculeAtoms

Chemical levelAtoms combine to form molecules.

Cellular levelCells are made up ofmolecules.

Tissue levelTissues consist of similartypes of cells.

Organ levelOrgans are made up of different typesof tissues.

Organ system levelOrgan systems consist of differentorgans that work together closely.

Organismal levelThe human organism is made upof many organ systems.

Smooth muscle cell

Smooth muscle tissue

Connective tissue

Blood vessel (organ)

HeartBloodvessels

Epithelialtissue

Smooth muscle tissue

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Atoms – the smallest units (building blocks) of matter.Molecules – make up organelles and other cellular components

macromolecules – proteins, carbohydrates, fats, DNA

Organelles – microscopic structures in a cell that carry out its individual functionsCells – smallest unit of life

CellsThe smallest units of an organism that carry out all the basic functions of lifePerform all activities necessary to maintain life

Metabolism, digestion, assimilation, excretion, reproduction

Tissues A mass of similar cells and cell products that form discrete region of an organ and performs a specific function

Four Tissue ClassesEpithelial: covers and protectsConnective: binds and supports other tissuesMuscle: movementNervous: connects sensory structures to motor structures

OrgansStructure composed of two or more tissue types that work together to carry out a particular function Cells integrated into tissuesServe a common functionExamples

BrainHeartLungsPancreas

An Organ System is a group of organsProtection, support, and movement

Integumentary - Skeletal - Muscular

Coordination and controlNervous - Endocrine

CirculationCardiovascular - Lymphatic

Nutrition and fluid balanceRespiratory - Digestive - Urinary

Production of offspringReproductive

The Human Body

NailsSkin

Hair

(a) Integumentary System Forms the external body covering, and protects deeper tissues from injury. Synthesizes vitamin D, and houses cutaneous (pain, pressure, etc.) receptors and sweat and oil glands.

Bones

Joint

(b) Skeletal System Protects and supports body organs, and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals.

Skeletalmuscles

(c) Muscular System Allows manipulation of the environment, locomotion, and facial expression. Main- tains posture, and produces heat.

Brain

NervesSpinalcord

(d) Nervous System As the fast-acting control system of the body, it responds to internal and external changes by activating appropriate muscles and glands.

Pineal gland

PituitaryglandThyroid

glandThymus

AdrenalglandPancreas

Testis

Ovary

(e) Endocrine System Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells.

(f) Cardiovascular System Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood.

Heart

Bloodvessels

Lymphaticvessels

Red bonemarrow

Thoracicduct

Thymus

Spleen

Lymphnodes

(g) Lymphatic System/Immunity Picks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells (lymphocytes) involved in immunity. The immune response mounts the attack against foreign substances within the body.

Nasalcavity

Bronchus

Pharynx

Larynx

Trachea

Lung

(h) Respiratory System Keeps blood constantly supplied with oxygen and removes carbon dioxide. The gaseous exchanges occur through the walls of the air sacs of the lungs.

Liver

Oral cavity

Esophagus

Largeintestine

StomachSmallintestine

RectumAnus

(i) Digestive System Breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces.

Kidney

Ureter

UrinarybladderUrethra

(j) Urinary System Eliminates nitrogenous wastes from the body. Regulates water, electrolyte and acid-base balance of the blood.

Prostategland

Ductusdeferens

Penis

Testis

Scrotum

Ovary

Uterinetube

Mammaryglands (inbreasts)

Uterus

Vagina

Overall function is production of offspring. Testes produce sperm and male sexhormone, and male ducts and glands aid in delivery of sperm to the femalereproductive tract. Ovaries produce eggs and female sex hormones. The remainingfemale structures serve as sites for fertilization and development of the fetus.Mammary glands of female breasts produce milk to nourish the newborn.

(k) Male Reproductive System (l) Female Reproductive System

All cells depend on organ systems to meet their survival needs Organ systems work cooperatively to perform necessary life functions

Digestive system Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces)

Respiratory systemTakes in oxygen and eliminates carbon dioxide

Food O2 CO2

Cardiovascular systemVia the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs

Interstitial fluid

Nutrients

Urinary systemEliminates nitrogenouswastes andexcess ions

Nutrients and wastes pass between blood and cells via the interstitial fluid

Integumentary system Protects the body as a whole from the external environment

Blood

Heart

Feces Urine

CO2

O2

Metabolism and Its Regulation

All the life-sustaining chemical reactions that occur within body cellsTypes of metabolism

Anabolism – reactions that build (synthesize) larger, more complex structures from simpler substances.

Similar to building a pearl necklace from individual pearls.In cells, anabolic reactions require ATP for energy.

Catabolism – reactions that breakdown larger, more complex substances to simpler substance.

Similar to removing each individual pearl from a pearl necklaceCatabolic reactions, like glycolysis, release energy. This energy can be used in cells to make ATP.

stable internal conditions regardless of external conditions

fluctuates within limited range around a set point

Homeostatic Control Mechanisms – Mechanisms that help to maintain homeostasisThe body has hundreds of homeostatic mechanisms, including mechanisms to control:

Body temperature, blood sugar, blood pH, water balance, blood pressure, electrolyte balance, etc.

When these mechanisms don’t work normally, the result can be disease, dysfunction or death.

Involve continuous monitoring and regulation of many factors (variables)

Nervous and endocrine systems accomplish the communication via nerve impulses and hormonesUsually involves negative feedback loop

Negative feedback loops have 3 componentsReceptorControl CenterEffector

Body senses a change and activates mechanisms to reverse itThe response reduces or shuts off the original stimulusExamples:

Regulation of body temperature and blood pressure (two nervous system mechanism)Regulation of blood volume by ADH (an endocrine mechanism)

1. Receptor (sensor)Monitors the environment and responds to stimuli (changes in controlled variables)Reports changes to the control center

2. Control centerDetermines the set point at which the variable is maintainedReceives input from receptor when variable is out of rangeDetermines appropriate response; delivers instructions to the appropriate effector

3. EffectorReceives signal (command) from control center Provides the means to respond Response acts to reduce or enhance the stimulus (feedback)

Stimulusproduceschange invariable.

BALANCE

IMBALANCE

IMBALANCE

1

Stimulusproduceschange invariable.

Receptordetectschange.

Receptor

BALANCE

IMBALANCE

IMBALANCE

1

2

Stimulusproduceschange invariable.

Receptordetectschange.

Input: Informationsent along afferentpathway to controlcenter.

Receptor

ControlCenter

BALANCE

Afferentpathway

IMBALANCE

IMBALANCE

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2

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Stimulusproduceschange invariable.

Receptordetectschange.

Input: Informationsent along afferentpathway to controlcenter.

Output:Information sent alongefferent pathway toeffector.

Receptor Effector

ControlCenter

BALANCE

Afferentpathway

Efferentpathway

IMBALANCE

IMBALANCE

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2

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Stimulusproduceschange invariable.

Receptordetectschange.

Input: Informationsent along afferentpathway to controlcenter.

Output:Information sent alongefferent pathway toeffector.

Responseof effectorfeeds backto reducethe effect ofstimulusand returnsvariable tohomeostaticlevel.

Receptor Effector

ControlCenter

BALANCE

Afferentpathway

Efferentpathway

IMBALANCE

IMBALANCE

1

2

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Sweat glands activated

Shiveringbegins

StimulusBody temperaturerises BALANCE

Information sentalong the afferentpathway to controlcenter

Information sentalong the afferentpathway to controlcenter

Afferentpathway

Afferentpathway

Efferentpathway

Efferentpathway

Information sentalong the efferentpathway toeffectors

Information sentalong the efferentpathway to effectors

StimulusBody temperature falls

ReceptorsTemperature-sensitivecells in skin and brain

ReceptorsTemperature-sensitivecells in skin and brain

EffectorsSweat glands

EffectorsSkeletal muscles

Control Center(thermoregulatory

center in brain)

Control Center(thermoregulatory

center in brain)

ResponseEvaporation of sweatBody temperature falls;stimulus ends

ResponseBody temperature rises;stimulus ends

Sitting up in bed causes a drop in blood pressure in the head and upper thorax

Receptors in the arteries near the heart alert the control center in the brainstem

Control center in the brain sends nerve signals to the heart (effector)The effector (the heart) receives a command signal to increases the heart rate. This returns the blood pressure to normal

Failure of this to feedback loop may produce dizziness in the elderly

Blood drains fromupper body, creatinghomeostatic imbalance

Baroreceptors aboveheart respond to dropin blood pressure

Baroreceptors send signalsto cardiac center of brainstem

Blood pressure risesto normal; homeostasisis restored

Person risesfrom bed

Cardiac centeraccelerates heartbeat

Receptors sense decreased blood volume (as occurs with dehydration)

Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH)

ADH causes the kidneys (effectors) to return more water to the blood

The response enhances or exaggerates the original stimulus

May exhibit a cascade or amplifying effect

Usually controls infrequent events e.g.:

Enhancement of labor contractions by oxytocin

Platelet plug formation and blood clotting

Self-amplifying cycleleads to greater change in the same directionfeedback loop is repeated – change produces more change

Normal way of producing rapid changes occurs with childbirth, blood clotting, protein digestion, fever, and generation of nerve signals

Head of fetuspushes against cervix

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Oxytocin stimulates uterinecontractions and pushesfetus toward cervix

Nerve impulsesfrom cervixTransmittedto brain

Brain stimulatespituitary gland tosecrete oxytocin

Positive feedbackcycle is initiated.

Break or tearoccurs in bloodvessel wall.

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Positive feedbackcycle is initiated.

Break or tearoccurs in bloodvessel wall.

Plateletsadhere to siteand releasechemicals.

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2

Positive feedbackcycle is initiated.

Positivefeedbackloop

Break or tearoccurs in bloodvessel wall.

Plateletsadhere to siteand releasechemicals.

Releasedchemicalsattract moreplatelets.

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Feedback cycle endswhen plug is formed.

Positive feedbackcycle is initiated.

Positivefeedbackloop

Break or tearoccurs in bloodvessel wall.

Plateletsadhere to siteand releasechemicals (clotting factors).

Releasedchemicalsattract moreplatelets.

Platelet plugforms.

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Fever > 104 degrees Fmetabolic rate increasesbody produces heat even fasterbody temperature continues to risefurther increasing metabolic rate

Cycle continues to reinforce itself

Becomes fatal at 113 degrees F

Disturbance of homeostasis Increases risk of disease Contributes to changes associated with aging May allow destructive positive feedback mechanisms to take over (e.g., heart failure)

Anatomical Position - Standard frame of reference for anatomical descriptions & dissection

Anatomical Divisions – The two fundamental divisions of the human body (axial & appendicular)

Body Regions – Regional terms designate specific areas

Directions - Consistent terms are used to designate position and direction to avoid inaccuracy.

Planes - implies an imaginary flat surface passing through the body

Cavities - Internally, the body is divided into spaces, or cavities, that contain organs.

Standard anatomical body position:Person stands erectface & eyes facing forwardFeet flat on floor, slightly apartArms at sidesPalms face forward (forearms in supine position)

When supinatedpalms face forward or upwardradius & ulna are parallel

When pronatedpalms face rearward or downwardradius & ulna are crossed

supine prone

Axial region = head, neck & trunkthoracic region = trunk above diaphragmabdominal region = trunk below diaphragm

divided into 4 quadrants / 9 regions by tic-tac-toe grid

Appendicular region = upper & lower limbsupper limb - arm (brachial region), forearm (antebrachial region), wrist (carpal region), hand (manual region), fingers (digits)lower limb - thigh (femoral region), leg (crural region),ankle (tarsal region), foot (pedal region), toes (digits)

Cervical

Pubic(genital)

CephalicFrontalOrbitalNasalOralMental

ThoracicAxillaryMammarySternal

AbdominalUmbilicalPelvicInguinal(groin)

Upper limbAcromialBrachial (arm)AntecubitalAntebrachial (forearm)

Carpal (wrist)Manus (hand)PalmarPollexDigital

Lower limbCoxal (hip)Femoral (thigh)PatellarCrural (leg)Fibular or peronealPedal (foot)Tarsal (ankle)MetatarsalDigitalHallux

ThoraxAbdomenBack (Dorsum)

Cervical

Back (dorsal)

Scapular

Vertebral

Lumbar

Sacral

Gluteal

Perineal (between anus and external genitalia)

Upper limb

Acromial

Brachial (arm)

Olecranal

Antebrachial (forearm)

Manus (hand)

Metacarpal

Digital

Lower limb

Femoral (thigh)

Popliteal

Sural (calf)

Fibular or peronealPedal (foot)

Calcaneal

Plantar

Cephalic

Otic

Occipital (back of head)

ThoraxAbdomenBack (Dorsum)

Nuchal (back of neck)

Plane: Flat surface along which body or structure is cut for anatomical studySagittal plane

Divides body vertically into right and left partsProduces a sagittal section

Midsagittal (median) planeLies on midline

Parasagittal planeNot on midline

Plane implies an imaginary flat surface passing through the body

Sagittal plane divides body into right and left regionsmidsagittal (median) plane divides body or organ into equal halvesparasagittal plane divides body into unequal parts

Frontal (coronal) plane divides body into anterior & posterior portionsTransverse (horizontal) plane divides the body into superior & inferior portions

Section implies actual cut or slice to reveal internal anatomy

Transverse plane

Median (midsagittal) plane

Frontal plane

Liver

Spleen

Pancreas

Aorta

Vertebralcolumn

Spinal cord

Subcutaneous fat layerBody wall

Rectum IntestinesLeft andright lungs

Liver HeartStomach

SpleenArm

(a) Frontal section (through torso)

(b) Transverse section (through torso, inferior view)

(c) Median section (midsagittal)

Dorsal cavityProtects nervous systemTwo subdivisions:

Cranial cavityEncases brain

Vertebral cavityEncases spinal cord

Ventral cavityHouses internal organs (viscera)Two subdivisions (separated by diaphragm):

Thoracic cavityAbdominopelvic cavity

Cranialcavity(contains brain)

Dorsalbodycavity

Vertebralcavity(contains spinal cord)

Cranialcavity

Superiormediastinum

Pericardialcavity withinthe mediastinum

Pleuralcavity

Vertebralcavity

Abdomino-pelviccavity

Ventral bodycavity(thoracic andabdominopelviccavities)

Abdominal cavity(contains digestiveviscera)

Diaphragm

Pelvic cavity(contains urinary bladder, reproductive organs, and rectum)

Thoraciccavity(containsheart andlungs)

(a) Lateral view (b) Anterior view

Dorsal body cavityVentral body cavity

Thoracic cavity subdivisions:Two pleural cavities

Each houses a lungMediastinum

Contains pericardial cavitySurrounds thoracic organs

Pericardial cavityEncloses heart

Abdominopelvic cavity subdivisions:Abdominal cavity

Contains stomach, intestines, spleen, and liverPelvic cavity

Contains urinary bladder, reproductive organs, and rectum

Cranialcavity(contains brain)

Dorsalbodycavity

Vertebralcavity(contains spinal cord)

Cranialcavity

Superiormediastinum

Pericardialcavity withinthe mediastinum

Pleuralcavity

Vertebralcavity

Abdomino-pelviccavity

Ventral bodycavity(thoracic andabdominopelviccavities)

Abdominal cavity(contains digestiveviscera)

Diaphragm

Pelvic cavity(contains urinary bladder, reproductive organs, and rectum)

Thoraciccavity(containsheart andlungs)

(a) Lateral view (b) Anterior view

Dorsal body cavityVentral body cavity

Thin, double-layered membrane separated by serous fluid

Parietal serosa lines internal body wallsVisceral serosa covers the internal organs

Outer balloon wall(comparable to parietal serosa)Air (comparable to serous cavity)

Inner balloon wall(comparable to visceral serosa)

Heart

Parietalpericardium

Pericardialspace withserous fluidVisceralpericardium

(b) The serosae associated with the heart.

Right upperquadrant(RUQ)

Right lowerquadrant(RLQ)

Left upperquadrant(LUQ)

Left lowerquadrant(LLQ)

Abdominopelvic QuadrantsAbdominopelvic QuadrantsDivisions used primarily by

medical personnel

Epigastricregion

Umbilicalregion

Rightlumbarregion

Leftlumbarregion

Righthypochondriac

region

Lefthypochondriac

region

Hypogastric(pubic)region

Right iliac(inguinal)

region

Left iliac(inguinal)

region

Liver

Gallbladder

Ascending colon oflarge intestine

Small intestine

Appendix

Cecum

Diaphragm

Stomach

Descending colonof large intestine

Transverse colonof large intestine

Initial part ofsigmoid colon

Urinary bladder

(a) Nine regions delineated by four planes (b) Anterior view of the nine regions showing the superficial organs

Abdominopelvic RegionsAbdominopelvic RegionsNine divisions used primarily by anatomists