Nervous Tissue – Structure, Location, Characteristics, Functions and Types

Structure of Nervous Tissue

Nervous Tissue – Structure: Nervous tissue is composed of cells called neurons, which send and receive messages to and from the brain and spinal cord. The brain and spinal cord are protected by the skull and vertebrae, respectively. Nervous tissue is also composed of supporting cells called glia. Glia nourish and protect the neurons and help to relay messages.

What is Nervous Tissue?

Nervous tissue is composed of cells called neurons that transmit electrical signals. It is found in the brain, spinal cord, and nerves. Nervous tissue enables the body to sense stimuli, process information, and respond to changes in the environment.

Structure of Nervous Tissue

• Nervous tissue is composed of cells that are specialized for transmitting and processing nerve impulses. The three types of cells found in nervous tissue are neurons, neuroglia, and satellite cells.
• Neurons are the cells that actually transmit the nerve impulses. They have a cell body, a single long process called an axon, and several shorter processes called dendrites. The axon carries the nerve impulse away from the cell body, and the dendrites carry impulses toward the cell body.
• Neuroglia are the supporting cells of the nervous system. There are several different types of neuroglia, including astrocytes, oligodendrocytes, and microglia. Astrocytes are the most common type of neuroglia and play a role in the repair and regeneration of nerve tissue. Oligodendrocytes form the myelin sheath around axons, and microglia are the immune cells of the nervous system.
• Satellite cells are cells that support neurons and neuroglia. They are found in the brain and spinal cord and play a role in the development and maintenance of the nervous system.

Nervous Tissue Location

Nervous tissue is located in the brain and spinal cord. It is responsible for transmitting information between the brain and the rest of the body.

Characteristics of Nervous Tissue

Nervous tissue is composed of neurons and neuroglia. Neurons are cells that process and transmit information. Neuroglia are cells that support and protect neurons. Nervous tissue is found in the brain, spinal cord, and nerves.

Function of Nervous Tissue

Nervous tissue is responsible for the transmission of nervous impulses throughout the body. It is made up of neurons and neuroglia. Neurons are specialized cells that transmit electrical signals, and neuroglia are supportive cells that assist in the function of neurons. Nervous tissue is found in the brain, spinal cord, and peripheral nerves.

Types of Nerves

There are three types of nerves: sensory, motor, and autonomic. Sensory nerves relay information from the body to the brain, motor nerves relay information from the brain to the body, and autonomic nerves regulate the body’s involuntary functions.

Motor Nerves

• Motor nerves are responsible for carrying messages from the brain to the muscles.
• The nervous system is composed of two main divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is composed of the brain and spinal cord, whereas the PNS includes all the other nerve cells in the body. The PNS can be further subdivided into the autonomic nervous system (ANS) and the somatic nervous system (SNS).
• The autonomic nervous system controls the involuntary actions of the body, such as the beating of the heart, the digestion of food, and the constriction and dilation of the blood vessels. The autonomic nervous system is subdivided into the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for the “fight or flight” response, whereas the parasympathetic nervous system is responsible for the “rest and digest” response.
• The somatic nervous system controls the voluntary actions of the body, such as walking, talking, and writing. The somatic nervous system is subdivided into the sensory nervous system and the motor nervous system. The sensory nervous system collects information from the body’s environment, and the motor nervous system transmits instructions from the brain to the muscles.
• The motor nerves are the nerves that control the movement of the muscles. There are two types of motor nerves: the alpha motor nerves and the gamma motor nerves. The alpha motor nerves are the nerves that control the movement of the skeletal muscles, and the gamma motor nerves are the nerves that control the movement of the smooth muscles.

Sensory Nerves

Sensory nerves are nerves that carry signals from the skin, muscles, and organs to the central nervous system. These nerves are responsible for sensations such as touch, pain, temperature, and vibration. A sensory nerve is a nerve that carries sensory information from the body to the brain. Sensory nerves allow us to feel things like pain, temperature, pressure, and vibration. They also allow us to taste, smell, and see.

There are three types of sensory nerves:

• The first type of sensory nerve is the afferent nerve. Afferent nerves carry sensory information from the body to the brain.
• The second type of sensory nerve is the efferent nerve. Efferent nerves carry sensory information from the brain to the body.
• The third type of sensory nerve is the mixed nerve. Mixed nerves carry both sensory and motor information.

Autonomic Nerves

There are three types of autonomic nerves:

• The sympathetic system arouses the body in times of stress or danger.
• The parasympathetic system conserves energy and restores the body to a resting state.
• The enteric system controls the digestive system.

Cranial Nerves

There are twelve pairs of cranial nerves.

• The first six pairs arise from the brainstem.
• The seventh, eighth, and ninth pairs arise from the cerebrum.
• The tenth and eleventh pairs arise from the cerebellum.
• The twelfth pair arises from the brainstem and the cerebellum.

1. Cranial nerve 1 is the olfactory nerve. It conveys smell information from the nose to the brain.
2. Cranial nerve 2 is the optic nerve. It conveys visual information from the eyes to the brain.
3. Cranial nerve 3 is the oculomotor nerve. It controls the movement of the eyes.
4. Cranial nerve 4 is the trochlear nerve. It controls the movement of the eyes.
5. Cranial nerve 5 is the trigeminal nerve. It controls the movement of the jaw, the taste of food, and the sensation of touch on the face.
6. Cranial nerve 6 is the abducens nerve. It controls the movement of the eyes.
7. Cranial nerve 7 is the facial nerve. It controls the movement of the muscles in the face and the production of tears and saliva.
8. Cranial nerve 8 is the auditory nerve. It conveys sound information from the ears to the brain.
9. Cranial nerve 9 is the glossopharyngeal nerve. It controls the movement of