heart

Question 1

Functions of the Cardiovascular System (3)

Answer 1

1. maintain homeostasis
2. transport of: metabolites/wastes, hormones/signal molecules, dissolved gasses, immune/inflammatory cells
3. regulation of body temperature

Question 2

Components (4)

Answer 2

1. Pump - the heart
2. Conducting Vessels - arteries/veins
3. Sites for exchange with tissues - capillaries
4. Drainage System for Excess tissue fluids - lymphatic vessels

Question 3

Arteries vs. Veins

Answer 3

Arteries: away from heart. Veins: back to heart

Question 4

Two Circuits?

Answer 4

1. Pulmonary circuit: to lungs
2. Systemic Circuit: to rest of body

Question 5

Pulmonary vs. Systemic Circuit Diagram

Answer 5

Question 6

Answer 6

Question 7

Answer 7

Question 8

Answer 8

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Location of heart ?

Answer 13

• heart resides in the mediastinum (middle of sternum)
• mediastinum: region of the thorax between the lungs/pleural cavities - contains heart, esophagus, trachea, thymus gland and large blood vessels

Question 14

Pericardium

Answer 14

• heart is contained within the pericardial cavity
• pericardial cavity is formed by pericardial sac

Question 15

Heart valves - occur between? insure?

Answer 15

• atria and ventricles (so blood only flows from atria to ventricles)
• ventricles and outflow vessels: pulmonary artery, artery
• valves insure: one way flow of blood - open to allow blood through, close to prevent backflow

Question 16

Blood Flow and Heart Valves (3)

Answer 16

• Tricuspid valve: right atrium and right ventricle
• Bicuspid/Mitral Valve: Left atrium/ventricle
• semilunar valves: pulmonary artery and aorta

Question 17

Cardiac cycle - def? what happens?

Answer 17

• all the events associated with one heartbeat
• the two atria contract while ventricles relax
• two ventricles contract whil atria relax

Question 18

Diastole vs Systole?

Answer 18

• diastole: relaxation phase
• Systole: contraction phase

Question 19

Blood Vessels - names of the three layers?

Answer 19

1. tunica interna
2. tunica media
3. tunica externa

Question 20

Tunica Interna (blood vessel)

Answer 20

composed of simple squamous epithelium (endothelium) and thin layer of CT

Question 21

Tunica media composition

Answer 21

thickest layer, composed of elastic fibers (to allow vessles to expand when ventricle contract and increase blood pressure) and smooth muscle (to control diameter of blood vessel)

Question 22

Tunica Externa - composition? attachment?

Answer 22

composed of connective tissue, attaches vessel to surrounding connective tissue = anchors blood vessel in place

Question 23

Elastic (Conducting) Arteries - properties? tunica media? function?

Answer 23

• largest diameter arteries (closest to the heart, like the aorta)
• tunica media contains high density of elastic fibers
• stretch and recoil in response to pumping of heart - even out pressure surges (so not a lot of pressure change in capillary beds)

Question 24

Muscular (Distributing) Arteries - size? function? tunica media? able to?

Answer 24

• medium sized arteries
• distribute blood to skeletal muscles and internal organs (by contracting and relaxing)
• tunic media: contains predominantly smooth muscle
• able to vasoconstrict (close) and vasdilate (open)

Question 25

Arterioles - size? layers? function?

Answer 25

* small to microscopic vessels * poorly defined tunica externa (so small, don't need much to anchor them) and media composed of few smooth muscle cells * deliver blood to capillaries - change in luminal diameter regulates blood pressure

Question 26

Capillaries - size? function?

Answer 26

* smalles blood vessels * connect arterioles to venules: mediate exchange between blood and surrounding tissues

Question 27

Control of Blood flow In Capillary Bed (2)

Answer 27

* precapillary sphincters: control blood flow through capillaries * metarterioles: shunt blood through capillary bed when sphincters closed

Question 28

Veins - direction?

Answer 28

collect blood from organs and tissues - return it to heart

Question 29

Venules - function? wall?

Answer 29

* collec blood from capillaries * wall composed of primarily tunica interna * are like wide capillaries

Question 30

Medium/Large Veins - properties of layers?

Answer 30

* tunica externa: thickest layer * lots of connective tissue, but not so much smooth muscle ( so small medium)

Question 31

Valves - found where? purpose?

Answer 31

* found in walls of veins (not found in arteries) for uppoer/lower extremities * prevent backflow of blood since blood has to travel against gravity * venous compression caused by contraction of adjacent muscle aids in maintaining blood flow

Question 32

Fluid Loss to Tissues?

Answer 32

* blood from capillaires to tissues: filtration from plasma into interstitial fluid * interstial fluid flows into lymphatic vessels - goes to veins back to heart

Question 33

Lymphatic Vessels - pressure? vessels? cell?

Answer 33

* lymphatic system at extremely low pressure * vessels very thin * endothelial cells discontinuous

Question 34

Lymph Flow vs. Blood Flow

Answer 34

* blood: actively pumped through vessels by heart * Lymph: flows passively along a pressure gradient, no pump

Question 35

Lymphatic Valves - number? purpose?

Answer 35

* large number of valves * prevent back flow of lymph