circulation

Question 1

what are the components of the the circulatory system? (3)

Answer 1

pumps, vessels and circulatory fluid

Question 2

What are the functions of the circulatory system?

Answer 2

maintenance of homeostasis

mass transport of solutes and cells

transport of heat

transmission of force

Question 3

What is the cardiac cycle?

Answer 3

one complete sequence of pumping and filling

inherent activity of the heart can be modified by outside influences

Question 4

What is systolic

?

Answer 4

heart muscles contracts, chambers pump blood

Question 5

What is the diastole?

Answer 5

heart muscle is relaxed, chambers fill with blood

Question 6

Regulation of the cardiac cycle four steps?

Answer 6

1) signal from SA node spread through atria
2) signal is delayed at AV node
3) bundle branches pass signals to heart apex
4) signals spread throughout ventricles

Question 7

blood returns to the heart via what?

Answer 7

due to contractions of skeletal muscles

Question 8

what do one way valves do?

Answer 8

ensure direction of blood flow towards heart

Question 9

Hoe does blood return back to the heart?

Answer 9

due to contractions of skeletal muscles

one way valves in veins ensure direction of blood flow towards heart

Question 10

regulation of blood flow:

Answer 10

blood volume < systemic volume

blood flow is directed at active tissues

Question 11

what are the control mechanisms of blood flow?

Answer 11

relaxing/ contracting of precapillary sphincters

constriction/ dilation of arteriols

Question 12

The lymphatic system:

functions of lymph system?

Answer 12

fluid balance- there is a net leakage of fluid and proteins from blood capillaries
-lymph capillaries collect lost fluid and return it to blood

Defence: lymph nodes have efence cells

Lymph capillaries pick up fat absorbed by the small intestine, transfer it to blood

Question 13

The lymphatic system:

How does movement work?

Answer 13

one way valves, contraction of skeletal muscles

lymph does not circulate in a closed circuit

Question 14

The lymphatic system:

what is thymus?

Answer 14

the site of maturation of T lymphocytes (immune system)

Question 15

The lymphatic system:

what are tonsils, what do they do?

Answer 15

handle infections in the mouth

Question 16

The lymphatic system:

what does the spleen do?

Answer 16

defence

red blood cell destruction

blood reservoir

Question 17

Blood:

composition?

Answer 17

cellular elements

plasma: blood minus the cells

Question 18

blood:

Volume?

Answer 18

heart rate (approx. 70 beats/min) x stroke volume (75mn) –> 5.25 L/min

Question 19

Blood:

Hematocrit?

Answer 19

packed cell volume

the normal value 45% is regulated

departures are either adaptive or pathological

Question 20

What is the origin of cellular elements in the blood?

Answer 20

from pluripotent stem cells in bone marrow

Question 21

What are leukocytes?

Answer 21

defense and immunity 5000-10000/mm3

Question 22

what are erythrocytes?

Answer 22

O2 and Co2 transport5-6 millionmm3

Question 23

What are platelets?

Answer 23

blood clotters 250000-400000/mm3

Question 24

Erythrocytes:

shape?

Answer 24

biconcave disk

small size

large surface area

Question 25

Erythrocytes: content?

Answer 25

Hemoglobin spectrin glycolytic enzyme carbonic anhydrase no organelles or ribosomes mammals: no nucleaus

Question 26

Erythrocytes what is spectrin?

Answer 26

predominant component of the membrane skeleton

Question 27

Erythrocytes what is glycolytic enzyme?

Answer 27

active carb metabolism

Question 28

Erythrocytes what is carbonic anhydrase?

Answer 28

catalyzes CO2 bicarbonate

Question 29

what is the process of the formation of erythrocytes?

Answer 29

takes four days, from stem cell to erythrocyte begins in bone marrow, completed in circulating blood initiated when not enough O2 reaches tissue

Question 30

What is the rate of formation of erythrocytes?

Answer 30

100 million cells per minute normally balanced with erythrocyte destruction can exceed destruction under conditions of tissue oxygen deficiency

Question 31

Destruction of erythrocytes

Answer 31

break apart in capillaries due to mechanical stress eaten by macrophages in spleen and liver

Question 32

Human red blood cells: life time?

Answer 32

life of 120 days lack mitochondria and nucleus

Question 33

Blood loss protection: in severe blood loss

Answer 33

decrease in blood pressure will result in decrease blood flow from damaged area constriction of blood vessels --> decrease blood flow coagulation

Question 34

Blood loss can be halted by what?

Answer 34

platelet plugs(form first) fibrin clots (form later)

Question 35

What are platelets activated by?

Answer 35

exposed collagen fibers in damaged tissue of vessel wall foreign surfaces thrombin

Question 36

What do platelets do upon activation?

Answer 36

form platelet plug release clotting factors change shape

Question 37

what do platelets contain?

Answer 37

actin and myosin to help contract chmicals that help the coagulation process to begin chemicals that attract other platelets chemicals that stimulate blood vessel repair chmicalls that stabalize blood clot

Question 38

What is stage 1 of clot formation?

Answer 38

sensing of damage clotting factors released from platelets are injured tissue plasma protein sythesized in liver circulate in inactive form

Question 39

What is stage two of clot formation?

Answer 39

Thrombin Activation - thrombin is enzyme absent from circulating blood - prothrombin circulates in plasma thrombin --> fibrinogen --> fibrin

Question 40

Stage three of clot formation

Answer 40

clot formation platelets -release substance that cause contraction of blood vessels - sticky platlets form plug - initiate formation of fibrin clot Fibrinogen - soluble protein in plasma fibrin- insoluble, fibrous protein clot seals wound intil vessel wall heals

Question 41

clotting dynamic: opposing clotting

Answer 41

heparin - anticlotting agent

Question 42

clotting dynamic favoring clotting

Answer 42

activated platlets, activated blood factors, thrombin, fibrin

Question 43

Clot dissolution is caused by what?

Answer 43

Fibrinolysis causes dissolution of fibrin and thrombus

Question 44

What is plasmin?

Answer 44

main enzyme of fibrinolysis cleaves fibrin in multiple locations acts to dissolve a fibrin clot produced in inactive form in the liver

Question 45

What is plasminogen?

Answer 45

cannot cleave fibrin, but has an affinity for it incorporated into the clot when it is formed

Question 46

Clot lysis is what?

Answer 46

complex process involving protocolytic enzymes, activators and inhibitors of plasmin and other proteases

Question 47

Cardiovascular disease: LDL HDL

Answer 47

LDL dilivers cholesterol to cells for membrane production HDH scavanges excess cholesterol for return to the liver

Question 48

When is there a risk of heart risk?

Answer 48

high LDL to HDL ratio als inflammation

Question 49

What are atherosclerosis caused by

Answer 49

the buildup of fatty deposits within arteries

Question 50

What is heart attack or myocardial infraction?

Answer 50

damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries, whcih supply O2 rich blood to heart muscles

Question 51

What is angina pecoris

Answer 51

chest pain caused by partial blockage of the coronary artery

Question 52

What is a stroke?

Answer 52

death of nervous tissue in the brain, usually resulting from rupture or blockage or arteries in the head effect of stroke depends on the extent and location of damaged brain tissue