Homeostatis

Question 1

Name 5 homeostatic mechanisms

Answer 1

-temp control
-blood pressure
-waste removal
-conc of nutrients in blood
-heart rate

Question 2

What is homeostasis and its aim

Answer 2

-The ability of the body to maintain relatively stable internal conditions even when the environment is changing and the activity of the individual is changing.
-This is a dynamic equilibrium
-Aim: body is supplied with sufficient nutrition and oxygen in comfortable conditions & functioning well

Question 3

The …….. system and the ………. System work together to control all homeostatic functions of the body.

Answer 3

Neural and endocrine

Question 4

Process of homeostatic control requires communication from different parts of the body……

Answer 4

Receptors, stimuli, control centre (afferent and efferent pathways), effector

Question 5

What are receptors?

Answer 5

-specialised cells that detect changes in internal and external conditions.
-send stimuli to the control centre

Question 6

What is a stimuli?

Answer 6

The change detected is a stimulus.

Question 7

What are the two different pathways in the control centre and define them.

Answer 7

1.-Afferent pathway: leads to the control centre
2.-Efferent pathway: leads from the control centre to the organ/ muscle which is then going to respond by secreting molecules or moving a part of the body -Will continue until a set point/ conc

Question 8

What is an effector

Answer 8

include muscles and glands - that produce a specific response to a detected stimulus.

Question 9

Answer 9

Question 10

Homeostatic mechanisms can be …………… or …………… or ………. (Give an example of each one )

Answer 10

-neural e.g. reflex
-hormonal e.g. negative feedback
-both e.g. positive feedback

Question 11

Answer 11

Question 12

Step by step of the cooling mechanism

Answer 12

1. The hypothalamus (the body’s thermostat) detects an increase in temperature.
2. This triggers vasodilation (widening of blood vessels) and diaphoresis (sweating).
3. These processes promote cooling, reducing the initial high-temperature stimulus.

Question 13

Step by step of the warming mechanism

Answer 13

1. The hypothalamus detects a drop in temperature.
2. This triggers vasoconstriction (narrowing of blood vessels) and shivering (muscle activity generating heat).
3. These responses help the body retain heat and increase temperature, counteracting the cold stimulus.

Question 14

What are the hormones involved in negative feedback control

Answer 14

-CRF (Corticotropin-Releasing Factor) - Released by the hypothalamus.
-ACTH (Adrenocorticotropic Hormone) - Released by the anterior pituitary.
-Cortisol - Released by the adrenal glands.

Question 15

How does the body respond to stress?

Answer 15

1. Adrenaline (fight-or-flight hormone) is released:
   o Heart beats faster (pulse increases).
   o Blood pressure rises.
   o Blood moves to muscles, and the liver releases extra energy (glucose).
2. Other Hormones Released:
   o Cortisol: Helps the body deal with stress.
   o Growth hormone: Repairs tissues and supports recovery.
   o The hypothalamus and kidneys adjust water levels and blood pressure through other hormones like ADH and aldosterone.

Question 16

CORTISOL
-glucose ( decreases/ increases)
-amino acids ( decrease/ increase)
- gluconeogenesis (decreases/ increases)
-protein break down to……….
-vasoconstriction (increases/ decreases)
-cartilage and bone formation ( decreases/ increases)
-blood pressure (increases/ decreases)
-inflammatory response (increases/ decreases)
-immune system (decreases/ increases)

Answer 16

-increases
-increases
-increases
-materials for growth and repair/ enzymes
-increases
-decreases
-increases
-decreases
-decreases

Question 17

GROWTH HORMONE
-anabolic (…….. and ………. Promotion)
-fat breakdown and release (decreases/ increases)
-glycogenolysis and release (decreases/ increases)
-cartilage formation (decreases/ increases)
-Skeletal growth (decreases/ increases)
-protein synthesis, cell growth soft tissue (decreases/ increases)

Answer 17

• metabolic, growth
  -increases
  -increases
  -increases
  -increases
  -increases

Question 18

What is positive feedback and give an example of it

Answer 18

-when a response to a stimulus strengthens until the stimulus is completely gone
-e.g. contraction in childbirth and blood clotting

Question 19

How does insulin regulate blood sugar levels?

Answer 19

When Blood Sugar is Too High:
1. The pancreas releases insulin.
2. Insulin helps:
o Cells absorb glucose from the blood.
o The liver stores extra glucose as glycogen.
3. Result: Blood sugar levels drop back to normal.

Question 20

How does glucagon regulate blood sugar levels?

Answer 20

When Blood Sugar is Too Low:
1. The pancreas releases glucagon.
2. Glucagon helps:
o The liver breaks down stored glycogen into glucose.
o Glucose is released into the blood.
3. Result: Blood sugar levels rise back to normal.

Question 21

Answer 21

Question 22

INSULIN

1-promotes ………. ………… and ………. ……….
2-………. development in the brain
3-…….amino acid peptide, ……chains S-S bridges
4-……. …….. of pancreatic islets

Answer 22

1-protein synthesis, fat storage
2-neural
3-51, 2
4-beta cells

Question 23

Insulin lowers blood glucose by……

Answer 23

-Enhances glucose uptake by cells, particularly muscle & fat cells
-Inhibits glycogenolysis - breakdown of glycogen
-Inhibits gluconeogenesis - conversion of amino acids or fats into glucose

Question 24

GLUCAGON

1-……. amino acid peptide
2-………. …….. of pancreatic islets
3-decreased by high ……..conc, ………. and ………
4-primary target …….. cells

Answer 24

1-29
2-alpha cells
3-glucose, insulin, somatostatin
4-liver

Question 25

Glucagon raises blood glucose by……

Answer 25

-Stimulates glycogenolysis - breakdown of glycogen to glucose -Stimulates gluconeogenesis - synthesis of glucose from lactic acid and from non-carbohydrate molecules -Stimulates release of glucose into blood stream