Co-ordination and Response in Humans

Question 1

what is the central nervous system made up of?

Answer 1

the central nervous system consists of the brain and the spinal cord

Question 2

what is a sensory neurone?

Answer 2

transmits nerve impulses from the sense organs or receptors to the central nervous system

Question 3

what is a relay neurone?

Answer 3

transmits nerve impulses from the sensory neurone to the motor neurone.

Question 4

where is a relay neurone found?

Answer 4

they are found within the central nervous system

Question 5

what is a motor neurone?

Answer 5

transmits nerve impulses from the central nervous system to the effectors

Question 6

how does a nerve impulse get transmitted from a neurone to another neurone?

Answer 6

nerve impulses are transmitted across a synapse via neurotransmitters from the (___ neurone) to the (___ neurone)

Question 7

what is the reflex action?

Answer 7

it is a involuntary action, an immediate response to a specific stimulus without conscious control

Question 8

what is the reflex arc?

Answer 8

a reflex arc is the shortest pathway which nerve impulses travel from the receptor to the effector in a reflex action

Question 9

describe the pathway taken when a person moves his arm reflectively away from a source of pain.

Answer 9

• [receptors] in the skin detect the** [pain >stimulus],** and a nerve impulse is generated
• the nerve impulse impulse is transmitted by a [sensory] neurone to the spinal cord to a** [relay]** neurone via neurotransmitters across a synapse
• the relay neurone transmits the nerve impulse to a [motor] neurone via neurotransmitters across a synapse
• the motor neurone transmits the nerve impulse to an [effector>arm muscle] via the ventral root
• the muscle **[reaction>contracts **]and moves the arm away

S,R,S,R,M,E,R

Question 10

what is the choroid?

Answer 10

contains a lot of blood capillaries, supplies nutrients to cells in the eye
- there is a layer of pigment(melanin) between the retina and choroid that absorbs light, to prevent reflection of light within the eye.

Question 11

function of the cornea?

Answer 11

it refracts or bend light rays into the eye

Question 12

what are the 2 kinds of photoreceptors in the retina?

Answer 12

rod cells and cone cells

Question 13

what are rod cells?

Answer 13

rod cells are photoreceptors in the retina, that detect light (black and white visions)
- they are present throughout the retina EXCEPT the fovea and the blind spot

Question 14

what are cone cells?

Answer 14

cone cells are photoreceptors in the retina, that detect light (red/green/blue)
- present at highest concentration at the fovea, absent at the blind spot

Question 15

pupillary reflex (when it is bright, what happens to the eye?)

Answer 15

Circular muscles of the iris > contracts
Radial muscles of the iris> relax
pupils> constrict
amount of light entering the eye> reduced

Question 16

pupillary reflex (when it is Dim, what happens to the eye?)

Answer 16

Circular muscles of the iris > relax
Radial muscles of the iris> contract
pupils> dilates
amount of light entering the eye> increase

Question 17

Accommodation reflex (when object of near to the eye)

Answer 17

Ciliary muscle>Contract
suspensory ligaments> slacken
lens> More convex
focal length> Shorten

Question 18

Accommodation reflex (when object of far from the eye)

Answer 18

Ciliary muscle>relax
suspensory ligaments> taut
lens> less convex
focal length> increase

Question 19

what is a endocrine system?

Answer 19

it is made up of endocrine glands throughout the body which secrete hormones into the blood stream .
hormones will have various effects on their target organs

Question 20

state 4 endocrine glands in the body

Answer 20

Pancreas, adrenal glands, gonads(testes in males, ovaries in females), pituitary glands

Question 21

What is an endocrine gland?

Answer 21

A group of cells of organ that secretes hormones

Question 22

What is a hormone?

Answer 22

A hormone is a chemical messenger, secreted by the endocrine glands into the blood. Hormones travel via the blood to target organs to exert their effects.

Question 23

how are hormones broken down?

Answer 23

Hormones are broken down in the liver after use, and excreted through the kidneys

Answer 24

(e) define a hormone as a chemical substance, produced by a gland, carried by the blood, which alters the
activity of one or more specific target organs and is then destroyed by the liver
(f) state what is meant by an endocrine gland, with reference to the islets of Langerhans in the pancreas
(g) outline how the blood glucose concentration is regulated by insulin and glucagon

Question 25

What are the 2 kinds of hormones?

Answer 25

Peptide and steroid
Peptide hormones> insulin and glucagon
Steroid hormones> sex hormones

Question 26

What happens after a hormone is sent to their target organs?

Answer 26

When hormones reach the target organ, they bind to receptors on cells.
The cells will respond to the hormone by changing their metabolic activity

Question 27

Describe what happens when the blood glucose level in the body is below normal?

Answer 27

(Stimulus) Blood glucose level below normal,
(Receptor) prancreas detects changes in the blood glucose level
(Effector) Islets of Langerhans in the pancreas secretes glucagon
(Effect on target organs) Liver and muscle cells are stimulated to increase conversion of glycogen to glucose. Stimulating the liver to release glucose into the blood.
Blood glucose returns to normal

Question 28

Describe what happens when the blood glucose level in the body is above normal?

Answer 28

(Stimulus) Blood glucose level above normal,
(Receptor) prancreas detects changes in the blood glucose level
(Effector) Islets of Langerhans in the pancreas secretes insulin
(Effect on target organs) Liver and muscle cells are stimulated to increase uptake of glucose from blood, and increase the conversion of excess glucose to glycogen for storage.
Blood glucose returns to normal

Question 29

What are the effects of adrenaline?

Answer 29

• increase metabolic rate
• increase heart rate and depth of ventilation
• causes the pupils to dilate
• increase blood pressure

Question 30

What is type 1 diabetes

Answer 30

It is genetic, person lacks insulin production