Homeostasis: Endocrine System In Humans

Question 1

What is homeostasis?

Answer 1

Maintaining a constant internal environment

Question 2

What is the endocrine system?

Answer 2

Hormones/chemicals released from glands.

Question 3

What are hormones?

Answer 3

> Chemical messegers

> Secreted from glands

> Travel from gland to target organ via bloodstream

》》estrogen
》》adrenaline

Question 4

Pituitary Gland

Answer 4

Master gland= release certain hormones which stimulate release of other hormones

》ADH
》TSH
》Growth hormones

Question 5

Adrenal

Answer 5

Secretes ADRENALINE

=Prepares body for physical activity or stressful situations

Question 6

Testes

Answer 6

Secretes TESTOSTERONE

= Controls development of male secondary sexual characteristics + involved in production of sperm

Question 7

Ovaries

Answer 7

Secretes OESTROGEN

=Controls development of female secondary sexual characteristics + involved in menstrual cycle

Question 8

Thyroid

Answer 8

Secretes THYROXINE

=Controls metabolic rate of body
How fast food broken down

Question 9

Pancreas

Answer 9

Secretes INSULIN + GLYGOCEN

=Controls blood glucose levels
How much sugar in blood

Question 10

What is osmoregulation?

Answer 10

Control of water levels + mineral ions (salt) in blood.

Question 11

How is water lost from body?

Answer 11

> Sweating

> Breathing

Question 12

Which organ controls osmoregulation?

Answer 12

Kidneys

Question 13

How do kidneys produce urine?

Answer 13

> Filtration of blood

> Selective reabsorption of useful substances:
》ALL glucose
》SOME salt ions
》SOME water

Question 14

Why are PROTEINS + GLUCOSE present in bloodstream but NOT urine?

Answer 14

Protein= molecules are TOO BIG to fit through kidney capillaries so continue in bloodstream.

Glucose= SELECTIVELY REABSORBED by kidneys to be used for respiration.

Question 15

Filtration + Selective Reabsorbtion in kidneys:

Answer 15

1- Blood passes through NEPHRON

2- Blood under HIGH PRESSURE- small molecules filtered out

3- Small mols pass into nephron tubule

4- Large mol (proteins) stay in blood- TOO BIG to fit through capillaries.

Question 16

What does ADH control?

Anti-diuretic hormone

Answer 16

Amount of water reabsorbed by kidneys.

Question 17

What happens to volume of urine when ADH is secreted?

Answer 17

> Causes more water to be reabsorbed into bloodstream via osmosis.

> Low volume of urine

> Urine= more concentrated

Question 18

What is ADH?

Answer 18

> Secreted from PITUITARY GLAND

> Makes membrane of kidney tubules more PERMEABLE

Question 19

What happens when water levels= TOO LOW?

Answer 19

1- Hypothalamus detects little water in blood

2- Pituitary gland SECRETES ADH into blood.

3- Walls of kidneys become MORE PERMEABLE

4- MORE water return to blood via OSMOSIS

5- LESS water= concentrated urine

6- Water levels= return to normal (negative feedback)

Question 20

What is dialysis?

Answer 20

> Machine procedure

> Removes waste products, excess ions + water.

> Concentration of dissolved substances in blood return to normal- using a machine.

Question 21

Advantages of Dialysis?

Answer 21

> Help kidneys function

> Prolongs life before transplant

Question 22

Disadvantages of Dialysis?

Answer 22

> Continuous Long process

> Controlled diet required

> Concentrations of substances in blood difficult to stabilise

> Risk of infection

> Risk to cause damage to tissues

Question 23

Kidney Transplant Advantages?

Answer 23

> No more diet restrictions

> Live fuller life

> Longer term

Question 24

Kidney transplant Disadvantages?

Answer 24

> Not enough donors

> Organ rejection

> Major surgery

Question 25

How is urea made?

Answer 25

> Digestion of proteins = excess amino acids > Liver- amino acids= ammonia by deanimation > Ammonia= toxic - needs to be secreted as urea

Question 26

What organ controls blood glucose?

Answer 26

Pancreas

Question 27

What does insulin do?

Answer 27

Allows glucose to move from blood into cells and store as glycogen

Question 28

What is glucagon?

Answer 28

A hormone that stimulates liver to break down glycogen->glucose

Question 29

What is Glycogen?

Answer 29

Storage carbohydrate found in liver + muscles

Question 30

What happens after eating?

Answer 30

1- Pancreas produces Insulin 2- Glucose in blood -> cells 3- soluble glucose -> glycogen (insoluble carbohydrate) 4- Insulin controls storage of glycogen 5- Stored glycogen converted back to glucose 6- Blood glucose = stable

Question 31

What happens to excess glucose?

Answer 31

Turns into LIPIDS (fats) =OBESITY

Question 32

What happens when there is low concentration of glucose in blood?

Answer 32

Release GLUCAGON 1- Breaks down glycogen -> glucose 2- Glucose released into BLOODSTREAM

Question 33

What is diabetes?

Answer 33

Blood glucose levels remain too high

Question 34

What is Type 1 Diabetes?

Answer 34

Blood glucose rises TOO HIGH -> pancreas doesn't produce ENOUGH insulin. > Treated by Insulin Injections

Question 35

What is Type 2 Diabetes?

Answer 35

Body stops responding to Insulin | Obesity

Question 36

What is Thyroxine?

Answer 36

Secreted by THYROID -> uses IODINE (diet) to produce > Controls BMR

Question 37

What hormone controls Thyroxine production?

Answer 37

Thyroid Stimulating Hormone | THS

Question 38

What happens when Thyroxine levels change?

Answer 38

Too HIGH = Pituitary gland REDUCES TSH production Too LOW = Pituitary gland INCREASES TSH Production (CONTROLLED BY NEGATIVE FEEDBACK)

Question 39

What gland produces adrenaline?

Answer 39

Adrenal

Question 40

What happens when adrenaline is not needed?

Answer 40

Adrenal glands STOP releasing adrenaline = Return to resting levels (NO NEGATIVE FEEDBACK LOOP)

Question 41

What is Negative Feedback System?

Answer 41

Maintains a steady state and works to restore original levels