B1.2 Nerves and Hormones

Question 1

Nerve

Answer 1

• Nerve = a bundle of neurones connected to brain or spinal cord.

Question 2

Stimulas

Answer 2

A change which causes a response in the body

Question 3

Receptors

Answer 3

Cells which detect change

Question 4

Sensory organ

Answer 4

Collection of receptor cells which respond to stimulas e.g EYE

Question 5

CNS

Answer 5

Made up of the spine and brain

Question 6

Impulse

Answer 6

Sn electrical signal passed along th nervous system

Question 7

Effector

Answer 7

• Effector = a structure that the nervous system causes to respond – a muscle or gland.

Question 8

What are synapses and how do they work

Answer 8

• Synapses = junctions between nerve cells.
• When a nerve impulse arrives at the end of a neurone, chemicals are released.
• These diffuse across the synapse, and cause a new nerve impulse in the next neurone.

Question 9

Steps of a reflex action

Answer 9

The main steps in a reflex action are:
A receptor detects a stimulus.
A sensory neuron transmits the impulse to the CNS.
A relay neuron passes the impulse on.
A motor neuron is stimulated.
The impulse passes to an effector (muscle or gland)
Action is taken ( the response).A muscle contracts or gland secretes a hormone to bring about a respose.

Question 10

FSH

Answer 10

(FSH) is made by the pituitary gland and causes the egg to mature and oestrogen to be produced.

Question 11

Oestrogen

Answer 11

Oestrogen is produced by the ovaries and inhibits (stops) further production of FSH. It stimulates the production of LH and also stimulates the lining of the womb to develop to receive the fertilised egg

Question 12

LH

Answer 12

(LH) is made in the pituitary gland and stimulates the mature egg to be released from the ovary (ovulation).

Question 13

The atrificial control of fertility

Answer 13

The contraceptive pill may contain oestrogen and progesterone.

Question 14

What is IVF

Answer 14

IVF (in vitro fertilisation) is when the egg and the sperm are fertilised outside of the body. They then develop into tiny embryos which are then inserted into the womb of the mother

Question 15

Advangtages and disadvantages of IVF

Answer 15

ADVANTAGES:
Allows infertile people to have children
DIS:
==birth defects
==to expensive
==high wrisk of the bay having 
===cause multiple birth
==Against God and nature

Question 16

Gravitropism

Answer 16

SHOOT
-more auxin on the bottom 
-more growth
-curves upwards and grows against the force of gravity
ROOT
-leass

Question 17

What is homeostasis

Answer 17

It is maintaining a constant internal enviroment.

Question 18

Control in body:IONS

Answer 18

• The ion content of the body:
• Ions are lost via the skin when we sweat
• Excess ions are lost via the kidneys in the urine

Question 19

Control in the body; Blood sugar levels

Answer 19

Eating food rich in carbs puts a lot of glucose into your blood.
Insulin controls blood sugar levels.

Question 20

Control in the body;Temperature

Answer 20

• To maintain the temperature at which enzymes work best.

* They are sensitive to changes in temperature and work best at body temperature – 37oC.

Question 21

When your too hot

Answer 21

Hairs lie flat
lots of sweat is produced -when it evaporates it transfers heat
Blood vessels dilate,so it can radiate more heat.

Question 22

When your too cold

Answer 22

Hairs stand up to trap an insulating layer of air
very little sweat is produced
You shiver,the movement generates heat in the musceles
Blood vessels constrict

Question 23

Control in the body: Water

Your kidneys control the balance of water and mineral ions.

Answer 23

• The water content of the body:
• Water leaves the body:
• via the lungs when we breathe out
• via the skin when we sweat to cool us down.
• Excess water is lost via the kidneys in the urine

Question 24

Contaceptives

Answer 24

Oral contraceptives:

• Oral contraceptives contain hormones to inhibit FSH production so that no eggs mature.
• Oral contraceptives may contain oestrogen and progesterone to inhibit egg maturation.
• The first birth-control pills contained large amounts of oestrogen.
• These resulted in women suffering significant side effects

Question 25

IVF

Answer 25

IVF (in vitro fertilisation) is when the egg and the sperm are fertilised outside of the body. They then develop into tiny embryos which are then inserted into the womb of the mother

Question 26

The use of artificial plant hormones-Weed killers

Answer 26

Weed killers

• Chemicals that are used that are specific to the weeds eg dandelions.
• They cause the weed to grow very quickly.
• The weed cannot sustain this rate of growth and dies.

Question 27

The use of artificial plant hormones Rooting hormones

Answer 27

Rooting hormones

• Cuttings are taken from a plant.
• The cutting is dipped into rooting powders.
• The hormone causes cells in the cutting to develop into roots.