Clinical physiology

Question 1

Brain cortex responsible for

Answer 1

consciousness

Question 2

Thalamus responsible for

Answer 2

translation of sensorial and motor
information

Question 3

Limbic system is for

Answer 3

regulation of autonomic nervous system

Question 4

Reticular formation is for

Answer 4

suppression of brain cortex,
controlling the sleep-wake cycle

Question 5

Membrane potential

Answer 5

difference in electrical
potential between the interior and the exterior of biological cell

varying ionic concentrations across the membrane

Question 6

two types of cardiac muscle cells:

Answer 6

¡ Contractile cells (99%)
¡ Autorhythmic cells

Question 7

CO =

Answer 7

SV x HR

Question 8

Stroke volume depends on:

Answer 8

ventricular filling and ventricular emptying

Question 9

Increased heart rate means decreased time for diastole (filling of the heart) and therefore

Answer 9

reduced stroke volume.

Question 10

Severe bradycardia can decrease

Answer 10

cardiac output

• Especially if the heart is unable to compensate by increasing contractility

Question 11

PVR stands for

Answer 11

peripheral vascular resistance

Question 12

MAP =

Answer 12

CO x PVR

(cardiac output multiplied by peripheral vascular resistance)

Question 13

Severe tachycardia decreases CO, because there is not enough time for

Answer 13

diastolic filling

Question 14

Why does tachycardia contribute to myocardial ischemia?

Answer 14

Coronary perfusion decreases during tachycardia because coronary vessels are perfused during diastole only.

Question 15

3 main determinants in heart physiology:

Answer 15

¡ Preload
¡ Afterload
¡ Contractility

Question 16

Preload, also known as the

Answer 16

left ventricular end- diastolic pressure (LVEDP), is the amount of
ventricular stretch at the end of diastole.

Question 17

Preload is affected by: (3)

Answer 17

¡ Venous return
¡ Compliance of ventricle wall
¡ Circulation blood volume

Question 18

Afterload, also known as the

Answer 18

systemic vascular resistance (SVR)

is the amount of resistance the
heart must overcome to open the aortic valve and push the blood volume out into the systemic
circulation.

Question 19

Excessively high tone of blood vessels (vasoconstriction)
increases effort of the heart muscle and can lead to decreasing of

Answer 19

stroke volume

Afterload is strongly affected by anesthetic drugs.

Question 20

primary modulator of vascular resistance

Answer 20

radius of the blood vessels

Question 21

In addition to blood vessel radius - 2 factors influencing peripheral resistance are

Answer 21

blood viscosity (e.g. dehydration, anemia) and

the length of the blood vessels

Question 21

Two determinants of mean arterial pressure:

Answer 21

cardiac output and peripheral vascular resistance

Question 22

Which tranquilizers/sedatives do not have a large effect on blood pressure? (2)

Answer 22

benzos
opioids

Question 23

Following administration of alfa-2-agonists, blood pressure typically sees what changes?

Answer 23

biphasic effect:

generally result in an
initial hypertension followed by reflex bradycardia, a fall in cardiac output and then an extended period of hypotension.

Question 24

The process of respiration can be divided into three events:

Answer 24

¡ Ventilation of the lungs by in- and outflow of air into the alveoli

¡ Lung gas exchange

¡ Tissue gas exchange

Question 25

Elephant lungs unique in what way?

Answer 25

In elephants, the lungs are attached to the chest wall by fibrous tissue so the ability to move the chest is
critical!

As opposed to in other mammals, the lungs slide freely against the pleura (pleural fluid and negative pressure aids smooth motion).

Question 26

Name 2 Obligate nasal breathers:

Answer 26

horses,
rabbits

Must always have open nostrils!

Question 27

Respiratory minute volume =

Answer 27

total volume of air that an animal breathes per minute

Question 28

Define lung vital capacity versus inspiratory capacity.

Answer 28

Inspiratory capacity is the volume of air that can be inspired following a normal, quiet expiration and is equal to tidal volume + inspiratory reserve volume.

Vital capacity is the volume of air under voluntary control, equal to (inspiratory reserve volume + tidal volume + expiratory reserve volume).

Question 29

Define functional residual capacity.

Answer 29

the volume of air present in the lungs at the end of passive expiration.

Question 30

Anatomical dead space:

Answer 30

respiratory pathway without air exchange (nose to bronchioles)

Question 31

MV stands for

Answer 31

minute volume which refers to the amount of gas inhaled or exhaled from a person’s lungs in one minute

Question 32

MV =

Answer 32

TV x RR

minute ventilation equals tidal volume multiplied by respiratory rate

Question 33

Each hemoglobin molecule is
able to bind

Answer 33

up to four molecules of O2.

Question 34

Diff between PaCO2 and PACO2.

Answer 34

partial pressure of CO2 in arterial blood and partial pressure of CO2 in alveoli

Question 35

(primary moderating stimulus of
respiratory rate and depth)

Answer 35

central chemoreceptors respond
to changes in level of CO2 in the blood

Question 36

Peripheral chemoreceptors in carotid and aortic bodies monitor..?

Answer 36

O2 level but Do not affect respiration due to the dominant
influence of CO2.

Only very low level of PaO2 (<60 mmHg) can stimulate breathing.

Question 37

Opioids and alpha2-agonists suppress the response of
central chemoreceptors to

Answer 37

to CO2 thus only high level of CO2
can stimulate the receptors.

Question 38

Alpha2-agonists contribute to what gas exchange issue?

Answer 38

ventilation perfusion
mismatch (low blood pressure)

A V/Q mismatch happens when part of your lung receives oxygen without blood flow or blood flow without oxygen.

Question 39

driving force behind oxygen release into tissues is

Answer 39

partial pressure of oxygen

(related to the hemoglobin dissociation curve: in the lungs where PaO2 is high, hemoglobin binds O2 but in the tissues where PaO2 is low hemoglobin releases O2)

Question 40

Hypoxemia and hypoxia

Answer 40

Hypoxemia – low level of partial pressure of oxygen in the arterial blood.

Hypoxia – inadequate oxygen level in tissue.

Question 41

Opioids directly change the thermoregulatory set
point of the anterior hypothalamus and

Answer 41

increase the metabolic rate.

Question 42

In relation to thermoregulation: Tranquillizers and sedatives reduce

Answer 42

the responsiveness of the hypothalamus to temperature changes.

Question 43

The only treatment for true episodes of malignant hyperthermia is

Answer 43

an intravenous injection of
the muscle relaxant in addition to supportive intravenous fluid therapy,
immediate removal of the patient from gas anesthetics, external cooling and respiratory support

Question 44

partial pressure of oxygen refers to?

Answer 44

the free O2 molecules dissolved in solution (plasma)

oxygen in a gas phase in equilibrium with the blood. pO2 only reflects a small fraction (1 – 2 %) of total oxygen in blood that is dissolved in blood plasma.

The remaining 98 – 99 % of oxygen present in blood is bound to the hemoglobin in the erythrocytes.

Question 45

what is the autoregulation zone

Answer 45

the brain and kidneys are able to modulate blood flow between MAP 60-160 mmHg.

below and above that range is problematic and blood flow is compromised to the above organs.

Question 46

types of shock (4)

Answer 46

distributive shock
(eg, sepsis, systemic inflammatory response syndrome)

hypovolemic (e.g. hemorrhage, severe dehydration)

circulatory/obstructive (e.g. GDV, percardial effusion)

cardiogenic (e.g. CHF, arrhythmias, cardiac tamponade)

Question 47

2 most important parameters to check in shock patient

Answer 47

heart rate
temperature
(only later - blood pressure)