Nervous System of Human Body

Brain and nervous system of human body

In this system thread structure like nerves are spread throughout the human body .They receive information from the environment by our sensitive organs [example skin]. after that these impulses reach to our brain resulting in movement of our body.

There are three types of neurons in human body

1. sensory neuron -it takes message from skin to brain.
2. connecting neuron-it transfer message from sensory to motor neuron
3. motor neuron -it transmit message from brain to the muscles .

neuron system is divided into three parts:

1. central nervous system
2. peripheral nervous system 
3. autonomic nervous system

A . Central Nervous System

it consists of brain and spinal cord .further brain is divided into three parts:

1.Fore brain-it consist of cerebrum

2 Mid brain-this consist of corpora quadrigemina.

3 Hind brain-it consist of cerebellum ,pons ,medulla oblongata

their functions are following –

A. FORE BRAIN

Cerebrum is divided into few lobes:

LOBE	FUNCTIONS	NUMBER
frontal lobe	memory ,judgement, decision making ,overall consiousness and will power , calculation ,arrangement , works related to cognition /awareness	1 in number
temporal lobe	it is above ear and helps in hearing	2 in number
parietal lobe	temperature ,touch and pressure , coldness ,pain	2 in number
occipital lobe	responsible for vision	1 in number

 

• Brain tissue is made of white colored cells  [center of brain ].it is called white matter and some tissues of grey matter [periphery area of brain ] are present  in white matter called thalamus ,hypothalamus , basal nuclei [cross section view]and grey matter when we see through right and left cerebrum hemisphere

Thalamus

• it trasmiits sensory impulses  from spinal cord to thalamus ,then  thalamus distribute it to brain.so thalamus is considered as relay center for sensory impulses.

Hypothalamus

1. it is connected to pituitary gland .
2. pituitary gland has two lobes -anterior and posterior .anterior is connected to hypothalamus .it releases hormones [six].hypothalamus controlled anterior lobe for releasing hormones.
3. it is  also trigger human thirst center.
4. it also stimulates hunger.
5. it controls sleep wake cycle
6. it is also called temperature  regulating center.
7. it controls emotional reactions such as fear ,anger ,love etc

There are two types of movements in our body

1.   gross motor movements  [ like duster picking ,spoon]
2.   fine motor [needle , embroidery ]

Basal Nuclei

• controls fine motor movements of our body

Mid brain

• controls the coordination of movement of head and eye .
•  it started moving in the direction of sound .

Hind brain

1.pons and medulla have similar functions together they form respiratory center

• pons controls rate and depth of respiration [depend upon the need of oxygen in our body ]
• medulla initiates respiration [inspiration and expiration ]

2. they are called vaso motor center[they controls the movement of blood vessel of our body [through arteries and veins through squeezing and relesing ].it has also impact on the blood pressure .eg in case of stress , high cholesterol etc

3.they both act as a slavery center [saliva secretion ]

• medulla separately controls sneezing , vomiting [few involuntary acts ] and  connected to spinal cord

• cerebellum coordinates voluntary organs like tonge ,hands ,legs .
• spinal cord and our brain have covering called meaninges

1. innermost covering [ piamata]
2. arachnoid [middlemost]
3. Duramata [outer]

• liquid between  innermost and middle is known as CSF [CEBRO SPINAL FLUID ]. it is moving which protects brain and spinal cord  from injury because it acts as a cushion and shock absorber.
• it contains glucose and nourishes our brain and spinal cord

B.  Peripheral nervous system

1. it consists of  of the nerves coming from spinal cord [spinal nerves ] and brain [cranial nerves
2. somatic nervous system is also part of it .
3. 31 pairs of spinal nerves and 12 pairs of cranial nerves
4. it controls the voluntary organs [skeletal muscles ]
5. they can be sensory , motor or neuron type of nerves .

C    Automatic nervous system

•      it is also made up of brain and spinal nerves which goes to the internal organs  and blood vessels of the body
• it control the involuntary organs
• central nervous system
• it is divided into two parts mainly

a] Sympathetic Nervous System

• increases heart beat  and rate of respiration
• increases blood pressure
• dilation of pupil
• increase in blood flow to the skeletal muscles
• increase RBC  and sugar in the blood
• urinary sphincter get relaxed and reduces the rate of relaxation and contaction of intestinal muscles
• narrows down the blood vessels n the skin
• hairs gets erected
• reduction of secretion of  salivary glands
•  helps in clotting of blood
• collectively this affects fear ,pain and  anger

  b] Parasympathetic Nervous System

• its functions are to opposite of the sympathetic nervous system
• collectively this will effect feeling of joy and rest.