Biology Paper 2: Homeostasis and response

Question 1

What is the receptor in homeostasis?

Answer 1

Cells which detect stimuli / change in environment

Question 2

What is the effector in homeostasis?

Answer 2

A muscle or gland that will bring about response.

Question 3

What is the order in the maintenance of homeostasis homeostasis?

Answer 3

Stimulus

Receptor

Sensory neuron

Coordination centre

Motor Neuron

Effector

Response / Feedback mechanism

Question 4

How does the nervous reflex work?

Answer 4

When a stimulus is felt

The receptors feel the stimulus.

Which sends electrical signals that travel through the sensory neuron to the spinal cord.

In the spinal cord there is a relay neuron which allows the electrical signal to travel to the correct motor neuron which can be connected to a gland or muscle that causes it to contract or move.

Question 5

Name 3 common nervous reflexes.

Answer 5

Blinking

Breathing

Sneezing

Question 6

What are the gaps that links 2 nerve cells.

Answer 6

Synapse

Question 7

What happens at the synapse?

Answer 7

When an electrical impulse is sent to the end of a neuron.

It triggers the release of chemical neurotransmitter molecules.

Which move towards the membrane and fuse with them to release chemical transmitter molecules.

Which diffuse to the start of the other neuron.

That causes another electrical impulse to be generated.

Question 8

What is negative feedback?

Answer 8

A homeostatic mechanism that occurs when the body detects a change and makes an adjustment to return itself to normal.

Question 9

What does the coordination centre consist of?

Answer 9

The brain and spinal gland.

Question 10

What is the function of the relay neuron?

Answer 10

They are located in the Coordination centre where they carry signals between sensory and motor neurons.

Question 11

What are the disadvantages to your body having lower thyroxine?

Answer 11

Lower metabolism

Lower protein synthesis levels

Question 12

Where is thyroxine released?

Answer 12

Thyroid gland.

Question 13

How does the brain maintain ideal thyroxine release when thyroxine levels decrease or increase?

Answer 13

Electrical signals are sent to the brain.

Which determine whether the pituitary gland needs to release more / less thyroxine stimulating hormone.

Question 14

What are the effects of adrenalin being released.

Answer 14

Increased heart rate allows more oxygen pumped to muscles / cells.

Increased breathing rate allows more oxygen to the blood.

Glycogen reserves in muscle cells break down to release glucose for increased respiration.

Blood from digestive system redirected to skeletal muscles.

Pupils dilate allows more light in.

Question 15

How does the brain release adrenalin to flight / fight response?

Answer 15

Brain sends signals to the adrenal gland to release adrenalin.

Not negative feedback.

Question 16

What happens when the amount of thyroid stimulating hormone released from the pituitary gland increases?

Answer 16

More thyroxine is released from the thyroid, metabolic rate increases.

Question 17

Why is it important that adrenalin does not use a negative feedback loop?

Answer 17

once the danger/stress is over, normality is re-established [1] reduces the body’s energy consumption (the body uses a lot of energy during the ‘“fight or flight” response. [1]

Question 18

What is homeostasis?

Answer 18

The maintenance of a constant internal environment at optimal conditions.

Question 19

What are the 3 main components of homeostasis?

Answer 19

Receptor

Coordination centre

Effector

Question 20

How do hormones travel in the endocrine system?

Answer 20

The blood.

Question 21

How does the pancreas maintain glucose levels when blood glucose RISE?

Answer 21

Receptor cells in the pancreas detect a rise.

Insulin is released to the liver and muscles.

Which convert the glucose to glycogen.

Causing blood glucose to fall.

Question 22

How does the pancreas maintain glucose levels when blood glucose FALLS?

Answer 22

Receptor cells in the pancreas detect the fall.

Glucagon is released.

Which causes the glycogen to break down to glucose in the level.
Causing blood glucose to rise.

Question 23

Name one function of glucose in the body.

Answer 23

Provides energy

Question 24

Where is the FSH and what does it do?

Answer 24

Produced in the Pituitary gland.

Stimulate oestrogen release

Matures eggs

Question 25

Where is Oestrogen produced and what does it do?

Answer 25

Produced in the ovaries

Causes Uterus line thicken in preparation for implantation.

Stimulates LH release.

Question 26

Where is LH produced and what does it do?

Answer 26

Produced in the pituitary gland.

Stimulates Ovulation.

Question 27

Where is progesterone produced and what does it do?

Answer 27

Produced in empty egg follicle.

Inhibits LH and FSH release

It maintains the lining so embryo can develop.

Stops eggs from maturing and being released.

Mucus at cervix to prevent infection.

Question 28

How do you treat infertility when someone cannot ovulate?

Answer 28

Fertility drugs.

Question 29

Which of the following is an advantage and disadvantages of in vitro fertilisation?

Answer 29

Advantages:
Allows people to have children when having a blocked oviduct.

Disadvantages:

Expensive

Limited success rate

Physically draining