HUMAN ORGAN

SYSTEMS

Integumentary

SkeletalMuscular

NervousEndocrine

CardiovascularLymphatic

RespiratoryDigestive

Urinary

Reproductive

OrganLevel

Theheart

Cardiacmuscletissue

Tissue Level

Cellular Level

Heartmuscle

cell

Protein filaments

Complex proteinmolecule

Atoms incombination

Chemical orMolecular Level

OrganismLevel

OrganSystem Level

Levels of OrganizationFrom smallest to largest.

9A. BODY SYSTEMSAll body systems work together to maintain homeostasis and keep an organism alive.

1. NERVOUS SYSTEM

Coordinates & controls

all body functions and responses, both

voluntary & involuntary

Brain, spinal cord & nerves

Brain & spinal cord. Protected by layers of bone and tissue. Survival without it is impossible. Processes information and generates responses.

CENTRAL NERVOUS SYSTEM

All the nerves that extend from the CNS to all body systems or travel from body systems to the CNS. Not enclosed by bone. Survival without some of them is possible.

• Nerves traveling to the CNS feed the CNS with information from sensory receptors.•Nerves traveling away from the CNS carry responses to organs and muscles that need to be carried out.

PERIPHERAL NERVOUS SYSTEM

Messages sent through the nervous system (nervous impulses) travel fast using specialized cells (neurons) found in nerves. Usually have short-lasting effects on very specific organs and/or muscles.

NERVE ACTION

2. ENDOCRINE SYSTEM

Assists the nervous system in controlling

the body.

Endocrine glands

ENDOCRINE GLANDS

A collection of sex-specific, scattered, disconnected organs and glands who respond to instructions from the CNS.

Produce and release (secretion) chemical messengers called hormones. These hormones act on target cells and produce the desired responses.

OVERVIEW

Messages sent using hormones move slower than nerve impulses and use the bloodstream. Usually have longer-lasting effects on organs and/or muscles, and can affect many organs and muscles for long periods of time.

Ex: testosterone and estrogen are secreted at puberty. Their effects last a lifetime in boys and until menopause in girls.

HORMONAL ACTION

• Insulin: Secreted by pancreas when there is too much glucose in the blood. Lowers blood glucose by making liver and muscles take in glucose and store it as glycogen.

• Glucagon: Secreted by pancreas when there is little glucose in the blood. Raises blood glucose by making liver and muscles convert glycogen to glucose, and then release the glucose into the blood.

• Oxytocin: Secreted by hypothalamus during childbirth. Induces uterine contractions and cervix dilation so that the baby can come out.

• Antidiuretic hormone (ADH): Secreted by hypothalamus when the body is in danger of dehydration. Makes the kidneys absorb water from the pee, producing small amounts of highly concentrated pee.

• Prolactin: Secreted by the pituitary. Stimulates the production of milk in the mammary glands following childbirth

• Adrenalin: Secreted by the adrenal glands in response to “fight or flight” situations. Prepares the body system to handle stressful, potentially dangerous situations.

• Cortisol: Secreted by adrenal glands. Regulates glucose metabolism and can suppress the immune system, reducing inflammations and fever.

HORMONES TO REMEMBER

• Melanocyte-stimulating hormone (MSH): Secreted by pituitary. Stimulates skin melanocytes to release melanin in response to excessive sunlight. Gives you a tan!

• Growth hormone (GH): Secreted by pituitary. Every body system responds to this one! Stimulates mitosis and the production of bone and muscle tissue, amongst many effects.

• Thyroxine: Secreted by the thyroid gland. Regulates metabolism during growth and development.

• Testosterone: Secreted by testes. Stimulates the development of primary & secondary sexual characteristics in males.

• Estrogen: Secreted by ovaries. Stimulates the development of primary & secondary sexual characteristics in females.

• Follicle-stimulating (FSH) stimulates oogenesis in girls & spermatogenesis in boys.

• Luteinizing hormone (LH) stimulates ovulation in girls and testosterone production in boys.

3. CARDIOVASCULAR SYSTEM

Main transport & communications

network.

Heart & blood vessels.

The main components are the flowing blood, the vessels (arteries, veins and capillaries), and the heart itself.

The blood carries everything the cells may need to survive (oxygen, amino acids, sugars, antibodies, hormones, clotting factors, white blood cells, lipid molecules...). All these components diffuse from capillaries and supply cells with nutrients. At the same time, waste molecules like carbon dioxide diffuse into the blood.

COMPONENTS

• Arteries and the smaller arterioles have thick but elastic muscular walls to withstand high blood pressures. Arteries carry oxygenated blood away from the heart at high pressure.

ARTERIES

• Capillaries are the smallest vessels in the CVS. They have walls one-cell thick to allow nutrient, wastes, O2 and CO2 to diffuse to-and-from cells. They form capillary beds around cells and tissues.

CAPILLARIES

• Veins and the smaller venules have thin muscular walls since blood pressure in veins is low. Valves keep blood flowing in one direction, preventing backflow. Veins carry deoxygenated blood back towards the heart.

VEINS

Muscle contraction &

valves push blood

back to the heart and

prevent backflow of

blood.

• Blood never leaves the vessels, and always travels in circles. Only nutrients do. Notice the structural differences between veins, arteries and capillaries.

• The heart is divided into four chambers: 2 atria (sing: atrium) and 2 ventricles.

• The heart is, in reality, two muscular pumps. The right side pumps deoxygenated blood to the lungs. The left side pumps oxygenated blood to the body.

• Valves in the heart exist to ensure that blood always travels in one direction and there is never any backflow of blood.

HEART

Pulmonary artery to lung

Rightatrium

Valve

Rightventricle

Leftventricle

Leftatrium

Pulmonaryartery to lung

Aorta to body

Pulmonaryveins from lungsPulmonary veins

from lungs

Inferior Vena Cavafrom body

Superior Vena Cavafrom body

Valve

Valve

Valve

Superiorvena cava

Pulmonaryartery

Capillariesof right lung

3

7

3

8

9

24

11

51

10

Aorta

Pulmonaryvein

Right atrium

Right ventricle

Inferiorvena cava

Capillaries ofabdominal organsand hind limbs

Pulmonaryvein

Left atrium

Left ventricle

Aorta

Capillariesof left lung

Pulmonaryartery

Capillaries ofhead andforelimbs

Every organ has its own blood-supplying artery...

...and is drained by its own vein.

4. RESPIRATORY SYSTEM

Supplies O2 to the body and

removes waste CO2.

Lungs & trachea (windpipe)

The heart sends deoxygenated blood to the lungs, and receives oxygenated blood from the lungs.

In the lungs, carbon dioxide is released and oxygen is taken in. Exercise will increase the amount of carbon dioxide in the body, and so the brain reacts by making the lungs breath faster and deeper.

LUNG ACTION

5. DIGESTIVE & EXCRETORY SYSTEM

Supplies nutrients for growth, development

and energy needs.

Removes solid waste (feces).

Mouth, esophagus, stomach, liver,

pancreas, small & large intestine.

The digestive system is one long tube with specialized sections (esophagus, stomach, intestines)... but still one continuous tube that starts in the mouth and finishes in the anus.

•The mouth digests only carbohydrates.•The esophagus carries food from mouth to stomach. •The stomach digests only protein. •The small intestine digests everything (carbohydrates, lipids and proteins) and absorbs nutrients. •The large intestine absorbs water and turns indigestible matter into feces (poop).

“TUBE” ACTION

The pancreas is shared with the endocrine system and has both digestive and endocrine functions. It produces many digestive enzymes and digestive fluids. These products are used to digest food in the intestine.

The liver is a true multitasker! It has over 200 different roles. For digestion it produces bile salts, a chemical essential for the digestion of lipids.

PANCREAS & LIVER

Digestive enzymes break down large polymers into small monomers that are easily absorbed.

Bloodstream

Veins to heart

Lymphaticsystem

Small intestine

Esophagus

StomachLipids

Mouth

Hepatic portal vein

Absorbed food(except lipids)

Absorbedwater

Acids and enzymesfrom the stomach

Enzymes and bile saltsfrom pancreas and liver

Liver

Rectum

Anus

Largeintestine

Think of the digestive system as a huge disassembly tube where food is broken down and then absorbed.

6. URINARY SYSTEM

Cleans & filters blood.

Removes liquid waste (urine).

Kidneys & bladder.

Kidneys filter the blood, removing wastes and toxic compounds. Produce urine, a fluid that contain mostly urea, a waste product of protein metabolism.

They also remove excess water (drinking too much) or, in response to the hormone ADH, absorb necessary water and prevent dehydration.

OVERVIEW

7. MUSCULAR SYSTEM

Makes body motion and balance possible.

Add a degree of protection to organs

and internal structures.

Muscles.

8. SKELETAL SYSTEM

Supports body against gravity, protects internal

organs, produces red and white blood cells, stores minerals and provides “hooking

points” for organs.

Skeleton.

• Bones meet in joints, held together by ligaments (straps of tissue that act as “holding tap”).

• Muscles attach to bones via tendons, another type of holding strap.

• Don’t confuse tendons with ligaments! Tendons hold muscle to bone, ligaments hold bone to bone.

• Many motor injuries are the result of torn or worn out ligaments and tendons.

9. INTEGUMENTARY SYSTEM

Protects body from the environment by

acting as a nonspecific defensive

barrier.

Only organ visible from the outside of

the body.Skin is considered an

organ; the biggest organ in the body!

Skin, nails, hairs.

10. LYMPHATIC & IMMUNE SYSTEMS

Protects body from dangerous threats

(pathogens).

Spleen, lymph nodes, thyroid gland.

11. REPRODUCTIVE SYSTEMS

Generates genetic variation, makes

gametes.Nourishes and

develops an infant (females).

Testes & penis.Ovaries, uterus &

vagina

SEXUAL CHARACTERISTICSPrimary sexual characteristics refer to the reproductive systems themselves (in males, testes and penis. In females, uterus and ovaries). These systems mature during puberty.

Secondary sexual characteristics refer to those features that indicate sexual maturity (ability to reproduce), such as:• Facial hear, increased muscle mass and ability to obtain erections in males. • Widening of hips, development of breasts and onset of menstruation.

GAMETOGENESISMales have spermatogonia, cells that divide by meiosis to produce sperm.

Females have oogonia, cells that divide by meiosis to produce ova (eggs).

Crossing over during meiosis is a key factor in the evolutionary process. Sexual reproduction is the preferred method of reproduction of almost all eukaryotes due to its ability to generate genetic variation.

1. Carbon dioxide is produced when cells break down nutrients for energy. Which of the following pairs of systems would participate in removing the carbon dioxide from the body?

a) Endocrine & circulatoryb) Circulatory & respiratoryc) Respiratory & endocrined) Reproductive & excretory

Answer: b

2. The respiratory system depends on the nervous system for signals to...a) enhance the amount of available oxygen in the lungs. b) coordinate muscles controlling breathing.c) release enzymes to increase the exchange of gases. d) exchange gases with the circulatory system.

Answer: b

3. Which of the following is a function of the nervous system?a) releasing ATP into contracting muscles. b) signaling muscles to contract.c) produce lactic acid in tired muscles. d) increase cellular respiration in muscles.

Answer: b

4. Which of the following pairs provides structural support for a human?

a) skin & blood. b) bones & muscles.c) spine & heart. d) brain & nerves.

Answer: b

5. Which three human body systems coordinate to cause an arm to move?

a) nervous, muscular, skeletal. b) respiratory, muscular, digestive.c) skeletal, circulatory, immune. d) digestive, nervous, circulatory.

Answer: a

6. Which of the following levels of organization BEST represents the sequence from smallest unit to largest?

a) Cell, organism, organ, tissue.b) Cell, tissue, organ, organ system.c) Cell, organism, tissue, organ system. d) Cell, tissue, organism, organ.

Answer: b

7. The homeostatic mechanism in humans that regulates blood pH depends on the feedback of information from...

a) stretch receptors. b) chemical receptors.c) hormone receptors. d) thermal receptors.

Answer: b

8. The diagram shows a human heart. When contracted the left ventricle pumps oxygenated blood to the body. What is the

a) Helps in pushing blood out into the left ventricle. b) Helps in pushing blood into the aorta. c) Prevents blood from flowing into the aorta. d) Prevents blood from flowing back into the left ventricle.

purpose of the aortic valve that separates the left ventricle from the aorta?

Answer: d

9. A diagram of a human knee is shown below. The structure labeled 1 is a...a) muscle.

b) joint.c) tendon.d) ligament.

Answer: d

10. As the level of O2 in the blood decreases and the level of CO2 increases, what is the body’s most likely response?

a) A decrease in heart rate. b) An increase in breathing rate.c) A decrease in blood pressure.d) An increase in the rate of digestion.

Answer: b