Nervous System(Human)

The nervous system is a rapid communication system .The main components are shown is fig
The control nervous system consists of :

• the brain ,situated inside the skull.
• the spinal cord,which extended from the base of the skull to the lumber region.

The spinal cord,protected from injury as it lies within the bones of the spinal column.The peripheral nervous system is a network of nerve fibres ,which are either:

or afferent nerves , which transmit signals from the body to the Brain or

Motor efferent nerves ,which transmits signals from the brain to the effector organs, such as muscles and glands.

The somatic senses are pain,touch, heat and cold. There sensation arise following stimulation of specialised sensory receptors at nerve ending found throughout the skin.

Nerve ending within the muscles and joints respond to change in the position and orientation of the body, maintaining posture and balance. Yet other sensory receptors are activated by stimuli in internal organs and control vital body functions

example: heart rate ,respiratory rate and blood pressure stimulation of any of these receptors sets up impulses that are conducted to the brain in sensory nerve .

communication along nerve fibers is by the electrical impulses that are generated when nerve endings are stimulated.nerve impulses can travel at a speed over the hundred metres per second, so responses response are almost immediate making a rapid and fine adjustments body function possible.

communication between nerve cell is also required since more than one nerve involved in the chain of event occurring between the initial stimulus and the reaction to it.

Nerve communicate with each other by releasing a chemical into tiny gaps between them. in only a few thousands of a second neurotransmitter quickly travel across the gap and either stimulates or inhibits the next nerve cell,thus ensuring the message is transmitted .

1.heart rate

2.blood pressure 

3.blood 
(click this word for more information)

heart rate

first rate the heart rate is a major determinant of cardiac output. If heart rate rises , cardiac output increases, and if it falls, cardiac output falls too. the main factor determining heart rate are outlined here.

1. Nervous System(Human)

2.blood pressure 

3.blood 
(click this word for more information)

Blood pressure

Blood pressure is the force or pressure that the blood on the walls of blood vessels.

Systematic arterial blood pressure maintain the essential flow of blood into and out of the organ of the body keeping blood pressure within normal limit is very important damage blood vessels, causing bleeding from sides of blood vessels rupture. Blood flow through tissue beds

may be inadequate . If blood pressure is too low. this is particularly dangerous for essential organs such as heart,brain or kidney.

Blood pressure Falls at rest and during sleep It increases with age and it usually higher in women than in men.
1. Nervous System(Human)

2.heart rate

3.blood 
(click this word for more information)

Blood

The blood is transport substances around the body through a large network of blood vessels.In adults body contains five-six litres of blood. It consist of two parts a fluid called plasma, and blood cells suspended in the plasma.

plasma .This is ninety% water with a wide range of substance dissolved or suspended in it there includes :

1) nutrients absorbed from the alimentary canal

2) oxygen absorbed from the lungs.

blood cells .there are three distinct groups, classified according to their functions

red blood cell transport oxygen to a lesser extent, carbon dioxide between the lungs and all body cells.

white blood cells are mainly concentrated with the protection of body against interfacing and foreign substances there are several type of leukocytes, which carry out their protective function in the different ways . this cells are larger and less numerous than erythrocytes.

1.Blood pressure(click here)

2 . Nervous System(Human)

3.heart rate

(click this word for more information)