Excretion, Co-ordination adn responses

Question 1

Where is water reabsorbed in the nephron

Answer 1

Loop of henle and collecting duct

Question 2

Where are salts reabsorbed in the nephron

Answer 2

Loop of Henle

Question 3

Where is glucose reabsorbed in the nephron

Answer 3

Proximal convoluted tubule

Question 4

Where is urea reabsorbed

Answer 4

They do not get reabsorbed

Question 5

3 differences between a nervous system and endocrine system (hormonal system)

Answer 5

• Nervous system transfer electrical impulses whereas endocrine system transfer chemical hormone
• Nervous system transfer by nerves/neurones whereas endocrine transfer by bloodstream
• Nervous system transfer at a very fast speed

Question 6

What makes up the central nervous system

Answer 6

Brain and spinal cord

Question 7

How an impulse is passed across a synapse

Answer 7

-An electrical impulse travels along an axon of the presynaptic neuron

• When the impulse reaches the nerve-ending, it releases neurotransmitters.
• Neurotransmitters will diffuse across the synapse and bind with specific receptor molecules on the membrane of the next neuron
• This stimulates the second to transmit the electrical impulses

Question 8

What happens at the nervous system when a person touches a hot object

Answer 8

• Receptor in the skin detects a stimulus (change in temperature)
• Sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the CNA. Relay neurons connect sensory neurons to motor neurons.
• Motor neuron sends electrical impulses to an effector

-Effector produces a response of moving hand away form the hot object

Question 9

Role of neurotransmitters at synapse

Answer 9

Released at the end of axon.

They diffuse across the synaptic clef.

Neurotransmitters will bind with receptor molecules on the membrane of the second neuron.

The binding of neurotransmitters to the receptor stimulates the second neuron to transmit an electrical impulse along its axon

Question 10

Function of the cornea

Answer 10

Transparent lens that refracts light as it enters the eye

Question 11

Function of the iris

Answer 11

Controls how much light enters the pupil

Question 12

function of lens

Answer 12

Transparent disc that can change shape to focus light onto the retina

Question 13

function of the retina

Answer 13

Contains light receptor cells - Rods (detect light intensity) and cones (detects colour)

Question 14

Function of the optic nerve

Answer 14

Sensory neuron that carries impulses between the eye and the brain

Question 15

Function of the pupil

Answer 15

Hole that allows light to enter the eye

Question 16

What happens to the eye when the person entered a dark room

Answer 16

• Radial muscles of iris contracted
• Circular muscles of iris relaxed
• Dilated pupil (more light enters eye)

Question 17

Eye change when looking at a near object

Answer 17

-Ciliary muscles contract
-Suspensory ligaments loosen
- Lens shape will be thicker
- Light is refracted strongly

Question 18

Eye change when looking at a distant object

Answer 18

• Ciliary muscles relax
• Suspensory ligaments tighten
• lens shape become thinner
• Light is only refracted slightly

Question 19

What is vasoconstriction and when does it happen

Answer 19

It happens when the person is cold. The arterioles will shrink, therefore it will be further away from the skin. Less heat will be lost and blood flow in skin capillaries will decrease

Question 20

What is vasodilation and when does it happen

Answer 20

It happens when the person is too hot. The arterioles will get wider so more heat will be lost as it is closer to the skin. The blood flow in skin capillaries will increase.

Question 21

Role of adrenaline and where is it produced

Answer 21

• produced in the adrenal gland
• Adrenaline increase the heart rate and breathing rate - insures glucose and oxygen can be delivered to muscle cells at a faster rate
• breaking down of stored glycogen to glucose and transfer them to active muscle cells

Question 22

where is insulin produced and what is it used for

Answer 22

• Produced in the pancreas
• Controls blood sugar level.

Question 23

where is testosterone produced and what is it used for

Answer 23

• Produced in the male testes
• responsible for the development of secondary sexual characteristics in males

Question 24

What does progesterone do and where is it produced

Answer 24

-Produced in the female ovaries
- Used for maintaining the uterus lining during pregnancy
- It stops the release of FSH andLH which releases the eggs.

Question 25

What does Oestrogen do and where is it produced

Answer 25

-produced by the female ovaries
- Used for the development of secondary sexual characteristics in females and regulating the menstrual cycle
- It causes growth and repair of the lining of the uterus wall

Question 26

How is the ADH used in osmoregulation

Answer 26

Water content of the blood falls below a certain if dehydrated.
More ADH released
collecting ducts more permeable for water to be reabsorbed
Less urine and more concentrated

Question 27

Where is LH and FSH produced and what do they do

Answer 27

They are both released in the pituitary gland
LH: Stimulates the ovary to produce progesterone
FSH: Causes egg to start maturing in the ovary. It also stimulates the ovaries to start releasing oestrogen.