Physiology

Question 1

What is the normal core temperature of the body?

Answer 1

37.8 degrees celcius

Question 2

What is the term used to decribe normal body temperature?

Answer 2

Normothermia

Question 3

What can cause variations in body temperature?

Answer 3

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

Question 4

In which two ways can the body gain heat?

Answer 4

1. Metabolic heat
2. Radiation from external environment

Question 5

How can the body lose heat?

Answer 5

• Convection
• Conduction
• Radiation
• Evaporation

Question 6

Which hormones can increase heat production and why?

Answer 6

Adrenaline, noradrenaline and thyroxine

These hormones can speed up metabolic rate, so more heat is produced

Question 7

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

Answer 7

Shivering

(increases muscular activity)

Question 8

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

Answer 8

1. The temperature gradient
2. Thermal conductivity

Question 9

Why does evaporation result in heat loss?

Answer 9

Energy is used to convert water from the lquid to gaseous state

Question 10

What are the two types of evaporation?

Answer 10

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

Question 11

Where can thermoreceptors be located?

Answer 11

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

Question 12

Where is the control centre for body temperature located?

Answer 12

Hypothalamus

Question 13

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

Answer 13

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

Question 14

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

Answer 14

Cold

Warmth

Question 15

When activated, what will the posterior hypothalamus cause?

Answer 15

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

Question 16

When activated, what bodily changes does the anterior hypothalamus confer?

Answer 16

• Vasodilatation
• Sweating
• Decreased muscle tone
• Behavioural changes - decreased movement, removal of excess clothing

Question 17

How is fever brought about?

Answer 17

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 to raise body temperature

Question 18

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

Answer 18

Hyperthermia

Question 19

What is hypothermia?

Answer 19

When the core body temperature decreases below 35 degrees

Question 20

What is homeostasis?

Answer 20

The process of maintaining an internal environment within the body that is optimal for function

Question 21

What are the two types of bodily control systems?

Answer 21

1. Intrinsic - within an organ (local controls)
2. Extrinsic - regulatory mechansims inititaed outside the organ and accomplished by nervous and endocrine systems

Question 22

With respect to homeostatic responses, what does the term “feedward” mean?

Answer 22

The change made by control systems in anticipation of another change