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Human biology > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (12)
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1
Q

What is homeostasis?

A

Maintenance of a constant internal environment?

2
Q

What is thermoregulation?

A

Regulation of body temperature; maintaining balance between heat loss/gain/production

3
Q

What is the normal body temperature?

A

~37.8 degrees Celsius, usually higher than environmental temperature

4
Q

What are the consequences of increased body temperature?

A

Nerve malfunction, change in protein structure, death

5
Q

Feedback loop: rise in body temperature?

A

Stimulus: rise in body temperature
Receptors: peripheral(skin and mucous membrane) heat thermoreceptors and central(hypothalamus) heat thermoreceptors
Modulator: hypothalamus
Effector: skin, blood vessels, thyroid glands(long term)
Response: sweating(evaporation), vasodilation, decrease in metabolic rate due to reduced thyroxine secretion(long term)
Feedback: reduction in body temperature

6
Q

What happens during heat exhaustion?

A

Volume of blood plasma and resistance to blood flow are reduced to extreme sweating and vasodilation, reducing blood pressure

7
Q

At what temperature does hypothermia start and what are the effect on the body?

A

Core body temperature falls below 33 degrees Celsius, metabolic rate becomes so low that heat production is unable to replace heat loss

8
Q

What is fluid balance?

A

Fluid loss must equal fluid gain

9
Q

How are fluids obtained?

A

Mostly obtained from water, small amount obtained from metabolic water

10
Q

Feedback loop: fall in body temperature?

A

Stimulus: fall in body temperature
Receptors: peripheral and central cold thermoreceptors
Modulator: hypothalamus
Effector: skin blood vessels, adrenal medulla, brain(parts increasing skeletal muscle tone),thyroid(long term)
Response: vasoconstriction, secretion of adrenaline and noradrenaline(increase cellular metabolism), shivering, increase in metabolic rate due to increased thyroxine secretion(long term)
Feedback: rise in body temperature

11
Q

Where does excretion occur and what does it excrete?

A

Lungs: excrete water vapor
Sweat glands: secrete water containing by products of metabolism
Alimentary canal: passes out bile pigment with faeces
Kidney(principal excretory organs): maintaining the constant concentration of materials in the body fluids

12
Q

Can water loss be regulated?

A

Water loss from the lungs and alimentary canal cannot be regulated, water lost from the kidneys can be