heart and blood vessels

Question 1

what are the two major divisions of the circulatory system

Answer 1

pulmonary and systemic circuit

Question 2

pulmonary circuit…where and what does it do

Answer 2

-right side of heart
- carries blood to lungs for gas exchange and back to heart

Question 3

systemic circuit…where and what does it do

Answer 3

-left side of heart
- supplies oxygenated blood to all tissues of the body and returns it to the heart

Question 4

where is the heart located

Answer 4

mediastinum, between lungs

Question 5

base of heart

Answer 5

wide, superior portion of heart, large vessels attach here

Question 6

apex of heart

Answer 6

tapered inferior end, tilts to the left

Question 7

pericardium…what is it, whats the function and how is it anchored

Answer 7

• double walled sac encloses the heart
• allows heart to beat w/o friction
• anchored to diaphragm inferiorly and sternum anteriorly

Question 8

the pericardium consists of 2 parts

Answer 8

fibrous pericardium- outer wall, dense irreg ct
serous pericardium - double layer
*parietal layer
*visceral layer

Question 9

parietal layer

Answer 9

outer layer is fused to fibrous pericardium

Question 10

visceral layer

Answer 10

called epicardium
- inner layer attaches to the surface of the heart

Question 11

3 layers of heart wall

Answer 11

epicardium
myocardium (cardiac muscle)
endocardium

Question 12

epicardium-made of and known as

Answer 12

-mesothelium (simple squamous) and areolar ct
- visceral layer of serrous pericardium

Question 13

myocardium function

Answer 13

muscle spirals around heart which produces wringing motion

Question 14

endocardium… what is it and made of

Answer 14

smooth inner lining of heart and blood vessels
- simple squamous epithelial tissue

Question 15

3 types of muscle

Answer 15

smooth
cardiac
skeletal

Question 16

cardiac muscle- location and control

Answer 16

• heart
• involuntary: hormones and autonomic neurons
• self-stimulating: impulses moves from cell to cell

Question 17

cardiac muscle- energy and contraction

Answer 17

-medium energy requirements
- medium contraction but spreads quickly
-does not fatigue…depends on aerobic respiration to make atp
- rhythmical contraction

Question 18

what joins intercalated discs

Answer 18

cardiomyocytes (branching cells)

Question 19

why do intercalated discs contain gap junction

Answer 19

-ions flow between cytoplasm of adjoining cells
- allow each cardiomyocyte to stimulate neighbours
- entire myocardium of either 2 atria or 2 ventricles act like a single, unified cell

Question 20

valve attachments

Answer 20

chordae tendineae
papillary muscles
trabeculae carneae

Question 21

watch video on blood flow through the chambers

Question 22

conduction system of heart…consists of

Answer 22

-cardiac conduction system
- nodal tissue

Question 23

cardiac conduction system is…

Answer 23

intrinsic

Question 24

nodal tissue, what does it do

Answer 24

coordinates contraction of atria and ventricles, electrical signals travel through gap junctions

Question 25

what is the pacemaker

Answer 25

sinoatrial node-initiates heartbeat and determines heart rate

Question 26

order of conduction system of heart

Answer 26

1. sinoatrial node-upper RA, initiates heartbeat and determines heart rate
2. signal spreads across to the LA
3. Atrioventricular node- base of the right atrium (embedded in interatrial septum). av signals the ventricles to contract moving along bundle branches
4. atrioventricular bundle (AV bundle) and bundle branches…signal leaves AV node, goes to l and r bundle branches, signal travels down interventricular septum
5. subendocardial conducting network (purkinje fibers). modified cardiomyocytes specialized for electrical conduction not contraction. once they deliver electrical signal- cardiomyocytes perpetuate it themselves by gap junctions

Question 27

why does the SA node fire spontaneously

Answer 27

ion movements
pacemaker potential
threshold and action potential
repolarization
repetition

Question 28

view chart of electrical behaviour of myocardium

Question 29

cardiac rhythm

Answer 29

-sinus rhythm…normal heartbeat triggered by SA. vagal tone-70-80bpm
-ectopic focus-region of spontaneous firing other than the SA node
*nodal rhythm-AV if SA is damaged
*if both av and sa nodes are damaged then its too slow to sustain life/ needs artificial pacemaker

Question 30

what is the cardiac cycle and what happens

Answer 30

al the events that occur during one heartbeat
-systole: contract of heart muscle
- diastole: relaxation of heart muscle
atria contract first simultaneously
ventricles contract simultaneously second

Question 31

watch a video on cardiac cycle

Question 32

electrocardiogram

Answer 32

composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on skin

Question 33

function of blood vessels and types

Answer 33

-transport blood and its content
- carry out gas exchange
- regulate BP
- direct blood flow

types: arteries, veins, capillaries

Question 34

arteries function

Answer 34

thick strong walls
transport oxygenated blood
AWAY from heart

Question 35

Veins function

Answer 35

thinner
carries deoxygenated blood BACK to heart

Question 36

vasoconstriction

Answer 36

blood flow from arteries to capillaries is restricted and blood pressure increases

Question 37

vasodilation

Answer 37

blood flow increases and BP decreases

Question 38

capillaries

Answer 38

nutrient and gas exchange

Question 39

capillary gas exchange…where and what

Answer 39

in thin capillary walls
nutrients/O2 leave and waste/CO2 enter

Question 40

what influences capillary gas exchange

Answer 40

blood pressure
diffusion
osmotic pressure

Question 41

venules function

Answer 41

drain blood from capillaries and merge to from veins