Physiology

Question 1

Describe diastole

Answer 1

when heart ventricles relax and fill with blood

Question 2

Describe systole

Answer 2

When ventricles contract and pump blood into aorta/pulmonary artery

Question 3

What is stroke volume?

Answer 3

The volume of blood ejected by by each ventricle per heart beat

Question 4

70-105 mmHg is the average range for what?

Answer 4

Mean arterial blood pressure

Question 5

Hypertensive is considered as what?

Answer 5

Blood pressure of 140/90 mmHg or higher/ daytime average of 135/85 mmHg or higher

Question 6

How would you describe the flow of normal blood?

Answer 6

Laminar

Question 7

How would you describe blood flow after an external pressure exceeding systolic BP is applied?

Answer 7

Non-existent

Question 8

When would you hear turbulent blood flow?

Answer 8

When the blood pressure is in between systolic and diastolic

Question 9

Which Korotkoff sound represents systolic BP

Answer 9

1

Question 10

Which Korotkoff sound represents diastolic BP

Answer 10

5

Question 11

How would you calculate the pressure gradient of blood?

Answer 11

MAP - CVP (central venous pressure- aka RA)

Question 12

How would you calculate MAP?

Answer 12

Diastoloc BP + 1/3 pulse pressure

Question 13

What does MAP relate to?

Answer 13

CO (SV x HR) x SVR

Question 14

What would happen to autonomic activity from baroreceptor reflex if BP was decreased?

Answer 14

decreased parasympathetic activity

increased sympathetic activity

Question 15

what would happen to autonomic activity from baroreceptor reflex if BP was increased?

Answer 15

increased parasympathetic activity

decreased sympathetic activity

Question 16

What happens when the heart is sympathetically stimulated?

Answer 16

Increased heart rate & increased contractile strength of heart (leading to increased SV)
This causes increased cardiac output
leading to increased MAP

Question 17

What happens when the veins are sympathetically stimulated?

Answer 17

increased vasoconstriction which increased venous return
thus increasing SV which causes a rise in cardiac output
causing a rise in MAP

Question 18

What happens when the arterioles are sympathetically stimulated?

Answer 18

increased vasoconstriction
leading to increased SVR (systemic vascular resistance)
this causes an increase in MAP

Question 19

What happens when the heart is parasympathetically stimulated?

Answer 19

decrease in heart rate
causing a decline in cardiac output
decrease in MAP

Question 20

What is autorhythmicity?

Answer 20

Heart’s ability to beat rhythmically in absence of external stimuli

Question 21

A heart controlled by the SA node produces which rhythm?

Answer 21

Sinus rhythm

Question 22

What does spontaneous pacemaker potential mean?

Answer 22

membrane potential is taken to a threshold to generate action potential in SA node cells

Question 23

In a 70kg young man how much is composed of exracellular fluid?

Answer 23

20%

Question 24

What makes up extracellular fluid?

Answer 24

Plasma volume x interstitial fluid volume

Question 25

What are the main factors that influence Extracellular fluid volume?

Answer 25

Excess/deficit of water and Na+ | i.e. salt/water balance

Question 26

What are the main hormone systems that regulate salt/water balance?

Answer 26

``` Renin-Angiotensin-Aldosterone-System Natriuretic peptides Antidiuretic Hormone (ADH) ```

Question 27

Which salt/water regulating hormones increase plasma volume?

Answer 27

RAAS | Antidiuretic hormone

Question 28

Which salt/water regulating hormones decrease plasma volume?

Answer 28

Natriuretic peptides

Question 29

what are the three components of RAAS?

Answer 29

1. Renin stimulates angiotensin I formation in blood from angiotensinogen 2. Angiotensin I is converted to angiotensin II by ACE (angiotensin converting enzyme) 3. Angiotensin II stimilates aldosterone release and causes systemic vasoconstriction- lease to thirst and ADH release- leads to increased plasma volume

Question 30

Where is renin produced?

Answer 30

kidneys- Juxtaglomerular Aparatus

Question 31

where is angiotensinogen produced?

Answer 31

liver

Question 32

where is angiotensin converting enzyme produced?

Answer 32

vasculo-pulmonary endothelium

Question 33

where is aldosterone released from?

Answer 33

adrenal complex

Question 34

What is the limiting step in RAAS?

Answer 34

renal secretion of renin

Question 35

what factors cause the limiting step in RAAS?

Answer 35

1. Renal artery hypotension 2. Stimulation of sympathetics 3. Decreased Na+ in renal tubular fluid

Question 36

When would natruiIetic peptides be released?

Answer 36

cardiac distension | neurohormonal stimuli

Question 37

What is the action of natriuretic peptides?

Answer 37

reduce blood volume and pressure due to excretion of Na+ and H2O in kidneys decreased renin release- decreased BP as renin is rate determining step vasodilator action- decreased SVR and BP

Question 38

what is the counter-regulatory system for RAAS?

Answer 38

Natriuretic peptides

Question 39

What are the two natriuretic peptides produced by the heart?

Answer 39

1. atrial natriuretic peptide (ANP) | 2. Brain type natriuretic peptide (BNP)

Question 40

What is an important clinical use of BNP?

Answer 40

it is measured in patients with suspected heart failure and is useful in giving a prognosis

Question 41

Where are Antidiuretic hormones produced?

Answer 41

hypothalamus of the brain | stored in the POSTERIOR PITUITARY

Question 42

what stimulates secretion of ADH?

Answer 42

1. reduced EFV (extracellular fluid volume) | 2. increased plasma osmolarity (MOST COMMON)

Question 43

What happens to the concentration of ADH when plasma osmolarity increases?

Answer 43

increased ADH

Question 44

What is the ADH action on kidney tubles?

Answer 44

Increases water reabsorbtion increases EV and plasma volume increases CO and MAP

Question 45

What are the stages of the cardiac cycle?

Answer 45

1. passive filling 2. atrial contraction 3. isovolumetric ventricular contraction 4. ventricular ejection 5. isovolumetric contraction