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
- sensory neuron -it takes message from skin to brain.
- connecting neuron-it transfer message from sensory to motor neuron
- motor neuron -it transmit message from brain to the muscles .
neuron system is divided into three parts:
- central nervous system
- peripheral nervous system
- 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:
|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|
||temperature ,touch and pressure , coldness ,pain
||2 in number
||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
- 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.
- it is connected to pituitary gland .
- pituitary gland has two lobes -anterior and posterior .anterior is connected to hypothalamus .it releases hormones [six].hypothalamus controlled anterior lobe for releasing hormones.
- it is also trigger human thirst center.
- it also stimulates hunger.
- it controls sleep wake cycle
- it is also called temperature regulating center.
- it controls emotional reactions such as fear ,anger ,love etc
There are two types of movements in our body
- gross motor movements [ like duster picking ,spoon]
- fine motor [needle , embroidery ]
- controls fine motor movements of our body
- controls the coordination of movement of head and eye .
- it started moving in the direction of sound .
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
- innermost covering [ piamata]
- arachnoid [middlemost]
- 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
- it consists of of the nerves coming from spinal cord [spinal nerves ] and brain [cranial nerves
- somatic nervous system is also part of it .
- 31 pairs of spinal nerves and 12 pairs of cranial nerves
- it controls the voluntary organs [skeletal muscles ]
- 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.