Anatomy Ch13 Nerve TIssue

Mississippi State University Professor: Mike Aaron

What major role does the Nervous System and Endocrine System have?

Maintaining Homeostasis in Human Body

Sensory Function of Nervous System

Senses changes (stimuli) within the body and external to the body

Integrative Function of Nervous System

analyzes sensory information, stores some aspects of the sensory information and makes decisions regarding the sensory information

Motor Function of Nervous System

responds to stimuli by initiating muscular contractions and glandrular secretions

Central Nervous System (CNS)

consists of the brain and spinal cord, it analyzes sensory information, creates emotions, thoughts and memories and stimulates muscle contraction and glandular secretion

Peripheral Nervous System (PNS)

connects the CNS to effectors (glands and muscles) throughout the body. It also relays sensory information from the body to the central nervous system.

What is the PNS made up of?

Nerves

Nerves

bundles of nerve fibers that are wrapped in fibrous connective tissue

Ganglion

Cluster of nerve cell bodies

Input Component of the PNS contains:

Sensory (Afferent) Neurons

Sensory (Afferent) Neurons

nerve cells that conduct nerve impulses from receptors in the body to the CNS. These inform the CNS of stimuli in or around the body

Output Component of the PNS contains:

Motor (efferent) Neurons

Motor (Efferent) Neurons

Nerve cells that carry impulses form the Central Nervous Sustem to effectors. This portion of the PNS allows the brain to signal muscles and glands to respon to commands

Effectors

Muscles and Glands

Major Divisions of the PNS

Somatic Nervous System (SNS) and Autonomic Nervous System (ANS)

Somatic Nervous System

contains sensory neurons that carry information from cutaneous and special sense receptors in the head, body wall and limbs to the CNS

The motor portion of the SNS is describes as what?

Voluntary, because motor neurons carry impulses

What do the sensory neurons do in the ANS

relay information from the internal organs ot the CNS

What do the motor neurons do in the ANS

carry impusles from the CNS to cardiac and smooth muscle, these motor neurons are described as being invol

What are the motor neurons described as in the ANS

Involuntary

2 Branches of the Motor Portion of the ANS

Sympathetic Division and Parasympathetic Division

Which two motor divisions of the autonomic nervous system (ANS) exert opposing (antagonistic) effects on internal organs?'

The Sympathetic Division and Parasympathetic Division

What two type of cells are in nerve tissue

Neuroglia and neurons

Neuroglia

Found throughout the nervous system, provide support and protection to neurons in the nervous system, also have the ability to undergo mitosis, which allows them to multiply in number, and maintain homeostasis of the nervous environment

Gliomas

tumors that arise from neuroglia

What are all the types of Neuroglia in the CNS

Astrocytes, Oligodendrocytes, Microglia, and Ependymal Cells

Astrocytes

Most abyndant type of neurological cell

Functions of the Astrocytes

1. Produce and absorb neurotransmitters

2. Maintain potassium levels in CNS… aids in production of nerve impuses

3. Help form the blood-brain barrier which regulate tentry of materials into the brain

4. Connect neurons and blood vessels together

5. provide sugar to neurons for ATP production

6. form hardened scar tissue when neurons are damaged.

   1. tissue fills the space of the one functioning neurons, problem with this astrocytes cannot produce impulses

Oligodendrocytes

produce myelin sheaths in CNS

Microglia

Phagocytic cells derived from monocytes (specialized leukocytes)… protect the CNS by engulfing microbes and foreign debris

Ependymal Cells

cuboidal epithelial cells, ciliated, line ventricles (cavities) within the brain. involved in the production of cerebrospinal fluid

What are the types of Neuroglia in the PNS?

Neurolemmocytes (schwann cells), and satellite cells

Neyrolemmocytes (schwann cells)

produce myelin sheaths around neyrons in the peripheral nervous system

Satellite cells

provide support to neurons in the PNS. Also aid in monitoring the chemical environment around neurons in the PNS

Neurons

come in variety of sizes, found all over body, can function for may years, limited ability to repair/replace themselves

What are the properties of neurons?

Excitability, conductivity, and secretion

Excitability

ability to respond to stimuli by creating and conducting impulses

Conductivity

ability to conduct impulses rapidly to other neurons or to effectors

Secretion

Neurons secrete neurotransmitters when the impusle reaches the end of the cell itself