Physiology

Question 1

Where are baroreceptors located?

Answer 1

Aortic arch
Carotid sinus

Question 2

Process of baroreceptor activation?

Answer 2

1. Sensitive to stretch
2. Firing rate increases when MAP increases (decreases/STOP when MAP decreases)

Question 3

What happens to baroreceptor firing if high blood pressure is sustained?

Answer 3

Firing decreases/STOP
They only respond to acute changes

Question 4

Definition of blood pressure?

Answer 4

The outwards (hydrostatic) pressure exerted by the blood on blood vessel walls

Question 5

Systolic pressure?

Answer 5

When the heart is contracting (normally <140mmHg)

Question 6

Diastolic pressure?

Answer 6

When the heart is relaxed (normally <90mmHg)

Question 7

MAP?

Answer 7

The average arterial blood pressure during a** single** cardiac cycle

Question 8

What is the average MAP range?

Answer 8

70-105mmHg

Question 9

MAP equations when you have diastolic and systolic?

Answer 9

MAP = [(2x diastolic) + systolic]/3
MAP = Diastolic + (pulse pressure/3)
MAP = DBP + 1/3 difference between SBP/DBP
MAP= [2x diastolic blood pressure (DBP)] + systolic blood pressure (SBP) /3
e.g if BP = 120/70 mmHg
DBP=70
SBP= 120

Question 10

MAP equations?

Answer 10

MAP = Cardiac output (CO) x Total peripheral Resistance (TPR)
MAP = Diastolic + (pulse pressure/3)

Question 11

CO equation?

Answer 11

CO = stroke volume (SV) x Heart rate (HR)

Question 12

How can MAP be regulated?

Answer 12

By regulating
-HR
-SV
-TPR

Question 13

Which vessels control resistance?

Answer 13

Arterioles
thus main site of systemic vscular reistnace becasue they distrubute blood into the capillary bed (smaller dimeters and so blood is sequeed more into the vessles )

Question 14

Tissue?

Answer 14

Group of cells with similar structure and specialized function

Question 15

General idea of how homeostasis works?

Answer 15

-Sense deviations from normal
-Integrate this information
-Make appropriate adjustments to restore controlled variable to a desired variable

Question 16

Intrinsic controls?

Answer 16

**Local controls inherent in an organ.
**

e.g organ is capable of maintaining homeostasis within itself. For example, the heart can control its own heart rate.

Question 17

Extrinsic controls?

Answer 17

Regulatory mechanisms initiated outside an organ
Accomplished by nervous and endocrine systems.

e.g controls of the cardiovascular system include neuronal, humoral, reflex, and chemical regulatory mechanisms

Question 18

Feedforward?

Answer 18

Responses made in anticipation of change

Question 19

Feedback?

Answer 19

A
Responses made after a change has occurred

Question 20

What does positive feedback do?

Answer 20

Amplifies a change

Question 21

What temperature is the body homeostatically maintained at?

Answer 21

37.8 celcius

Question 22

What does having normothermia optimise?

Answer 22

Cellular metabolism
Cellular function

Question 23

What is the term used to describe normal body temperature?

Answer 23

Normothermia نورموثيرميا

Question 24

What can cause variations in body temperature?

Answer 24

Natural differences between individuals
Time of day (lower in mornings)
Physical activity or emotions
Exposure to extremes of temperature
Menstrual cycle

Question 25

In which two ways can the body gain heat?

Answer 25

1. Metabolic heat 2.Radiation from external environment

Question 26

How can the body lose heat?

Answer 26

Convection Conduction Radiation Evaporation

Question 27

Which hormones can increase heat production and why?

Answer 27

Adrenaline, noradrenaline and thyroxine These hormones can speed up metabolic rate, so more heat is produced

Question 28

Besides hormonal/metabolic control, what is one mechanism utilised by the body to increase body temperature?

Answer 28

Shivering (increases muscular activity)

Question 29

The level of heat conduction is dependent on which two factors?

Answer 29

A 1. The temperature gradient 2. Thermal conductivity

Question 30

Why does evaporation result in heat loss?

Answer 30

Energy require to convert water on the skin to vapor.

Question 31

What are the two types of evaporation?

Answer 31

1. Passive - this happens continuously, water molecules diffuse from bodility surfaces 2. Active - the sympathetic nervous system is employed to increase sweating

Question 32

Where can thermoreceptors be located?

Answer 32

1. Central - hypothalamus, abdominal organs, other locations 2. Peripheral locations - skin

Question 33

Where is the control centre for body temperature located?

Answer 33

Hypothalamus

Question 34

What are the effectors used by the body to control temperature?

Answer 34

Skeletal muscle (shivering) Skin arterioles (dilatation/constriction) Sweat glands

Question 35

The posterior hypothalamus is activated by ______, whilst the anterior is activated by ______.

Answer 35

Cold Warmth

Question 36

When activated, what will the posterior hypothalamus cause?

Answer 36

- Vasoconstriction - Increased muscle tone -Shivering - Behavioural changes - voluntary movement/clothing changes

Question 37

How is fever brought about? A

Answer 37

Macrophages release pro-inflammatory mediators which act as endogenous pyrogens They stimulate prostaglandin release which causes the hypothalamus to raise the baseline body temperature that is maintained Shivering and vasoconstriction will be initiated by hypothalamus to raise body temperature

Question 38

Why is it called when the body temperature exceeds 40 degrees?

Answer 38

Hyperthermia

Question 39

What is hypothermia?

Answer 39

When the core body temperature decreases below 35 degrees

Question 40

What is homeostasis?

Answer 40

the maintenance of steady states within our bodies by coordinated physiological mechanisms. * in internal envirmonet

Question 41

Active evaporation is called?

Answer 41

Sweating - controlled by sympathetic nervous system

Question 42

What is the hypothalamus?

Answer 42

Small area in the brain Body's thermostat

Question 43

what is the feature of Negative feedback control ?

Answer 43

Promotes stability by regulation of a controlled variable through the flow of information along a closed loop. * happen oppose an initial change

Question 44

system which amplyfie intial chnage is known as ?

Answer 44

Postive feedback

Question 45

Feedforward

Answer 45

responses made in anticipation of a change

Question 46

when will Thermostat reset to normal ?

Answer 46

if pyrogen release reduced/stopped

Question 47

What effect does ATP hydrolysis have on the sodium potassium pump?

Answer 47

The ADP is released but the phosphate group phosphorylates the pump. causing Na+ to move outside the cell against the concentration gradient

Question 48

ANP - BNP -

Answer 48

* released in response to atrial distension. * important for heart failure diagnosis.

Question 49

ADH

Answer 49

Secretion stimulated by - reduced extracellular fluid volume or increased extracellular fluid osmolality. ADH acts in the kidney tubules to increase the reabsorption of water ie concentrate urine (anti-diuresis). ADH also acts on blood vessels to cause vasoconstriction.

Question 50

Basal Metabolic Rate.(BMR)

Answer 50

is the minimum amount of energy required to sustain vital body function and lead to basic level of heat production

Question 51

the steps of haemostasis

Answer 51

1) Constriction of the blood vessel 2) Formation of a platelet plug 3) Activation of the coagulation cascade 4) Formation of a fibrin plug

Question 52

E. Pinocytosis

Answer 52

Pinocytosis is the internalisation of fluids (and particles contained within) into cells through invagination of the cell membrane.