S1W1 L1: Gross and cellular structure of heart

Question 1

type of muscle cardiac muscle/ heart is formed from

Answer 1

striated

Question 2

loacted

Answer 2

behind sternum, 12-14cm ling

Question 3

three circulation circuits

Answer 3

pulmonary
coronary
systemic
all run in parallel, little/ no connection between 3 circuits

Question 4

coronary circulation: how is oxygenated blood supplied to the heart muscle

Answer 4

left and right coronary arteries, branch directly from aorta base

Question 5

anastomosis

Answer 5

surgical or natural connection between coronary arteries that supply blood to heart muscle

Question 6

coronary circulation: where does the venous blood from myocardium drain

Answer 6

coronary sinus then into right atrium, then to lungs via pulmonary circuit for reoxygenation

Question 7

what does the aortic arch connect

Answer 7

ascending aorta and descending aorta

Question 8

three elastic arteries that originate along the aortic arch:

Answer 8

brachiocephalic trunk
left common carotid artery
left subclavian artery

Question 9

what does the brachiocephalic trunk branch into

Answer 9

right subclavian artery
right common carotid artery

Question 10

where does brachiocephalic trunk supply

Answer 10

right arm and right side of head

Question 11

where does left common carotid artery supply

Answer 11

head and brain

Question 12

where does left subclavian artery supply

Answer 12

left arm

Question 13

what does descending aorta supply

Answer 13

thorax and abdomen

Question 14

what does the descending aorta split into and what does this supply

Answer 14

two common iliac, supplies the pelvic area

Question 15

what do the common iliac run into

Answer 15

femoral artery

Question 16

unpaired arteries which run off abdominal aorta and supply gastro-intestinal system

Answer 16

superior mesenteric
inferior mesenteric
celiac trunk

Question 17

what is the heart enclosed in (double walled sac)

Answer 17

pericardium

Question 18

fibrous pericardium

Answer 18

outer layer, protects, anchors and prevents the heart overfilling with blood

Question 19

serous pericardium

Answer 19

inner layer, extends to cover the epicardial surface of the muscular wall of heart

Question 20

pericardial cavity

Answer 20

filled with fluid, allows gliding motions of membranes, reduction of friction, means heart can stay mobile

Question 21

right AV valve

Answer 21

tricuspid

Question 23

left AV vavle

Answer 23

biscuspid/ mitral

Question 24

semilunar valves

Answer 24

each have three cusps
located at the entrance of the outflow tracts: pulmonary artery and aorta

Question 25

papillary muscles

Answer 25

attach to AV valves
important for stopping efflux of valves, help to create tension on valves to make sure they remain shut
do not pull valves closed

Question 26

fibroblasts

Answer 26

contained within extracellular matrix
provide mechanical support for heart, help to provide fixture for contractile cells

Question 27

endothelial types of endothelial cells in heart

Answer 27

endothelial (contribute to lining of blood vessels) and smooth muscle (in coronary arteries and veins)

Question 28

contractile cells

Answer 28

atrial and ventricular cardiomyocytes

Question 29

conduction cells

Answer 29

generation and passing electrical impulses through heart

Question 30

features of cardiomyocytes

Answer 30

rich in glycogen and myoglobin
large number of mitochondria
reflects high energy demand

Question 31

how are myocytes connected

Answer 31

intercalated disc

Question 32

two roles of intercolated disc

Answer 32

mechanical coupling
electrical coupling

Question 33

mechanical coupling: desmosome

Answer 33

cell to cell adhesion junction
provides mechanical strength and stability
small gap between membranes of adjacent cells filled with connective tissue
usually occur on transverse sections of intercalated discs

Question 34

electrical coupling: gap junction

Answer 34

longitudinal
connexins
allow passage of ions and small molecules between cells

Question 35

what do gap junction allow

Answer 35

ionic currents to pass through cells
AP evoked
heart behaves as a single cell functional syncytium
cardiac muscle obeys all or nothing principle

Question 36

what are the two pathways that excitability from the SAN spread through atrial tissue to the AVN

Answer 36

1. cell to cell via intercalated discs
2. internodal tract

Question 37

spread of excitation in heart:

Answer 37

1. SAN
2. AVN
3. ventricles