Homeostasis

Question 1

Define homeostasis

Answer 1

Process by which cells, tissues and organisms maintain the status quo/ maintain internal conditions despite changes.

Question 2

What is a negative feedback loop?

Answer 2

Loop where internal conditions are maintain, by returning high or lows levels back to normal.

Question 3

Give an example of a negative feedback loop?

Answer 3

Maintaining blood glucose levels, maintaining body temperature etc.

Question 4

What is a positive feedback loop?

Answer 4

Where the original stimulus is exaggerated/ emphasised.

Question 5

Give an example of a positive feedback loop?

Answer 5

Clotting cascade, Ferguson reflex (baby pushing against cervix)

Question 6

When does negative feedback loop stop?

Answer 6

When the effector ceases.

Question 7

When does positive feedback loop stop?

Answer 7

When the initiator/stimulus ends.

Question 8

What is the normal range of core body temperature?

Answer 8

37 plus/minus 0.5

Question 9

At what temperature is someone experiencing mild hypothermia?

Answer 9

32.1-35

Question 10

At what temperature is someone experiencing severe hypothermia?

Answer 10

28-32

Question 11

At what temperature is someone experiencing a fever?

Answer 11

38-40

Question 12

At what temperature is someone experiencing a heat stroke/heat exhaustion?

Answer 12

40

Question 13

What does the body do when you are too hot?

Answer 13

Vasodilation, sweating, pilorelaxation, stretching our

Question 14

What does the body do when you are too cold?

Answer 14

Vasoconstriction, shivering, piloerection, curling up

Question 15

What is the normal ph range for the human body?

Answer 15

7.35-7.45

Question 16

What are the major organs for maintaining acid base balance?

Answer 16

Lungs-respiratory balance and kidneys-metabolic balance

Question 17

What is the sensor for temperature in the thermoregulatory system?

Answer 17

Nerve cells in the skin and brain

Question 18

What is the control centre in the thermoregulatory system?

Answer 18

Hypothalamus

Question 19

Name the buffering systems in the human body?

Answer 19

Carbonic acid, sodium phosphate buffering system.

Question 20

How much water is in a 70kg man?

Answer 20

70 x 0.6= 42kg

Question 21

How much water is in females?

Answer 21

50% water in normal females- more fat

Question 22

How much water is in an infant?

Answer 22

70% - little fat

Question 23

What is osmolality?

Answer 23

Concentration of a solution expressed as the total number of solute particles per kilogram.

Question 24

Define isotonic?

Answer 24

Same water potential on both sides of the plasma membrane

Question 25

Define hypotonic?

Answer 25

Higher water potential outside the cell

Question 26

Define hypertonic?

Answer 26

Lower water potential outside the cell.

Question 27

What happens if there is not enough water?

Answer 27

Cells absorb water from interstitial space, then from one another, tissues die, then organs begin to die (end stage organ failure).

Question 28

What happens if there is too much water?

Answer 28

Osmotic pressure high, cells swell, enzyme and protein stop working and cells swell until they burst.

Question 29

What is oedema?

Answer 29

Fluid retention, peripheral oedema- swollen ankles

Question 30

What is hydrostatic pressure?

Answer 30

Force exerted by the fluid on the vessel wall.

Question 31

What is osmotic pressure?

Answer 31

Force applied by the solute/colloid to prevent osmotic movement across the membrane

Question 32

What causes oedema?

Answer 32

Hydrostatic pressure is greater than osmotic pressure, lymph blocked or damaged, presence of plasma proteins in interstitial space.

Question 33

Where do body fluids accumulate?

Answer 33

28kg -intracellular water 14kg -extracellular water (11kg- interstitial water and 3kg plasma)

Question 34

What is a standard mans circulating blood volume?

Answer 34

3litres plasma + 2litres red blood cells = 5 litres

Question 35

What is the condition where pH is too low?

Answer 35

Acidosis

Question 36

What are symptoms of acidosis?

Answer 36

Seizures, headaches, shortness of breath, high HR, vomiting, coma

Question 37

What is the condition where pH levels are too high?

Answer 37

Alkalosis

Question 38

What are the two main causes of acidosis?

Answer 38

Metabolic acidosis (increased production of metabolic acids) Respiratory acidosis (build up of carbon dioxide due to hypo ventilation)