1.1 Human nervous system

What does Human Nervous System consists of?

1.peripheral nervous system (cranial nerve 12, spinal nerves 31)

2.central nervous system (brain,spinal cord)

What are function of Human Nervous System? (5)

1.controls and coordinates organs and all the body parts

2.detects stimuli

3.sends information in the form of impulses

4.interprets impulses

5.produces appropriate responses

how many responses that human body does?

2, voluntary action and involuntary action.

What is voluntary action?

Are conscious actions and conducted under one's will . All voluntary actions are controlled by the brain

State 3 example of voluntary action.

1. Reading

2. Writing

3. Jogging

What is the pathway of impulse from affector to the affector? (VA)

stimulus--affector--nerve impulses--brain--nerve impulses--effector--response

What is involuntary action?

actions that occur immediately without conscious control or prior thoughts

What are involuntary action are classified into? (List 3 examples)

1.involving medulla oblongata- breathing,peristalsis,heartbeat

2.involving spinal cord (reflex action)- sneezing, withdrawing hand from hot object

What is the pathway of impulse from affector to effector? (IA)

stimulus--affector--nerve impulse-spinal cord--nerve impulse--effector--response

What are the 5 human sensory organ?

1.eye (sight)

2.nose (smell)

3.skin (touch)

4.ear (hear)

5.tongue (taste)

function of suspensory ligament

strong fibres which hold the eye lens in its position

Conjunctiva

Transparent membrane which protects the front part of the sclera

Sclera

Strong layer that maintains the shape of the eye and protects it

Eye lens

Transparent and elastic convex lens which focuses light onto the retina

Cornea

Transparent layer which refracts and focuses light onto the retina

Iris

The coloured part of the eye which controls the size of the pupil

Retina

Layer containing photoreceptors which detects light and produces nerve impulses

Yellow spot

Part of the retina which is most sensitive to light as it had many photoreceptors

Pupil

Opening in the center of the iris which controls the quantity of light entering the eye

Choroid

Black layer that prevents reflection of light in the eye and supplies oxygen and nutrients to the eye

Optic nerves

Nerve fibres which carry nerve impulses from the retina to the brain to be interpreted

Blind spot

Part of the retina which is not sensitive to light as there are no photoreceptors and an exit point for all optic nerve fibres

Aqueous humour

Transparent fluid which maintains the shape of the eyeball and focuses light into the eye

Vitreous humour

Transparent jelly-like substance which maintain the shape of the eyeball and focuses light onto the retina

Ciliary muscle

Muscle that changes the thickness of the eye lens through contractions and relaxations

what types of photoreceptors in the retina?

1.rod cells

2.cone cells

function of rod cells and characteristics

sensitive to different light intensities including faint light but not sensitive to the colours of light

function and characteristics of cone cells

sensitive to the colours of light under bright conditions.

3 types sensitive to red,green and blue light

how many part do ear have ?

1.outer ear

2.middle ear

3.inner ear

outer ear consists of what?

earlobe and ear canal

function of earlobe

Collects and directs sound waves into the ear canal

Function of ear canal

Directs sound waves into the eardrum

middle ear consists of what?

1.eardrum (thin membrane)

2.ossicles (small three bones)

3.oval window

4.eustachian tube

Function of Eardrum

Vibrates according to the frequency of the sound waves received and transfer the vibrations to the ossicles

Function of ossicles

Amplify sound vibrations and transfer them to the oval window

Function of oval window

Collects and transfers sound vibrations from the ossicles to the cochlea

Function of Eustachian tube

Balance the air pressure on both sides of the eardrum

inner ear consists of what

cochlea(contain fluid), semicircular canals (contain fluid),auditory nerve

Function of Cochlea(contain fluid)

Detects and converts sound vibrations into nerve impulses

Function of Semicircular canals( contain fluid)

Detects the position of the head and help to balance the body

Function of Auditory nerve

Send nerve impulses from the cochlea to the brain to be interpreted

how many sensory cells of smell do we have?

10 millions

where is the sensory cells of smell located?

at the roof of nasal cavity

what is the function of sensory cells for smell

Chemical substances in the air will dissolve in layer of mucus and then stimulate the cells to produce nerve impulses that are sent to the brain to be interpreted to determine the smel

Structure of tongue

Tiny nodules known as papillae on the surface of the tongue. The papillae is covered with hundreds of taste buds. Each taste buds contain 10 to 50 taste receptors

Taste receptors

Detect the tastes of sweet, sour, salty, bitter, umami

Function of taste buds

When food is chewed, part or all the chemical substances will dissolve in the saliva. These dissolve chemical substances will diffuse into the taste buds through the pores and stimulate taste receptors to produce nerve impulses. The nerve impulses are then sent to the brain to be interpreted to determine the type of tastes

5 types of skin receptors

Pain receptor, cold receptor, heat receptor, pressure receptor, touch receptor

What are the thin outer layer known as

epidermis

An inner layer known as

dermis

Parts of the skin that are less sensitive

Knee, elbow

What are the 2 type of layer found in the skin

epidermis and dermis