Lecture exam 3

Question 1

Physiology of EKG

Answer 1

P wave: depolarization of SA node
QRS complex: ventricular depolarization
T wave: ventricular repolarization

Question 2

Intrinsic conduction system

Answer 2

• cardiac muscle contracts independently of nerve impulses

~sets ❤️ rhythm
~ensures ❤️ muscle depolarization in ! direction (atria to ventricles)

Question 3

Heart physiology

Answer 3

Tachycardia-rapid heart rate, over 100 bpm
Bradycardia-slow heart rate, less than 60 bpm

-Cardiac output-amt. of blood pumped by ventricle by ❤️ in 1 min
-Stroke volume- volume of blood pumped by each ventricle in 1 contraption
-❤️ rate- 75 bpm

CO= HRx SV
CO= HR (75 bpm) x SV (70 bpm)
CO= 5250 ml/min= 5.25 L/min

Question 4

Details of cardiac cycle:

Answer 4

-1 complete heartbeat

systole=contraction
Diastole= relaxation

Atrial diastole (ventricular filling)- ❤️ is relaxed, BP is low, from atria to ventricles, semilunar valves closed

Atrial systole- ventricles relaxed, blood in ventricles, Intraventricular pressure rises, AV valves closed, ventricles closed

Ventricular systole- ventricles contract, semilunar valves open, blood goes into ventricles, atria are relaxed and filling with blood

Isovolumetric relaxation- ventricular contraption begins, pressure falls, semilunar valves close, ventricles are closed, atrial pressure increases, AV valves open

Question 5

Process of hematopoiesis: where it happens? How it occurs? What controls it?

Answer 5

-blood cell formation
-occurs in red bone marrow
- RBC’s are eliminated by phagocytes in spleen or liver, lost cells are replaced by hemocytoblasts in red bone marrow
-erythropoietin

Question 6

Steps and events of hemostasis:

Answer 6

1) Vascular spasms:
blood vessel constricts, slows blood flow
2) Platelet plug formation:
platelets becomes sticky and cling to collagen fibers, piles up to plug hole
3) Coagulation
Ca2+ trigger clotting, Prothrombin (inactive)–>thrombin (active), thrombin joins fibrinogen (inactive) –> fibrin (active) fibrin forms nets, forms clot

Question 7

Blood and hemostasis disorders:

Answer 7

Thrombus- a clot in broken vessel
Embolus- a thrombus floating free in bloodstream
Thrombocytopenia- low # of platelets
Hemophilia- normal clotting factors of missing

Question 8

Blood typing groups: Who can donate and recieve? Where it happens?

Answer 8

Blood Groups: Antibodies: Receive: Donate to:
A Anti-B A, O A, AB
B Anti-A B, O B, AB
AB neither A,B,AB,O AB
O Anti-A &B O A,B,AB,O

Question 9

Blood characteristics:

Answer 9

sticky, opaque fluid
O2 rich blood- scarlet red
O2 poor blood-dull red
ph 7.35-7.45

Question 10

Formed elements: (least to greatest)

Answer 10

Neutrophils - # ^ during infection, functions as phagocytes at infection, eats bacteria
Lymphocytes -Large w/ nucleus, inside lymphatic tissue, produce anit-bodies
Monocytes- largest WBC, function as phagocytes , eat cancer cells and chronic cells
Eosinophils - kills worms
Basophils - release histamine & heparin to innflammation