Nervous Tissue and Divisions- LECTURE

Nervous System

Communication and control system composed of nervous tissue including neurons and glial cells.

Central Nervous System (CNS)

Composed of the brain and spinal cord.

Peripheral Nervous System (PNS)

Includes cranial nerves and spinal nerves.

Nucleus (in CNS)

Group of neuron cell bodies in the central nervous system.

Tract (in CNS)

group of axons in CNS

Ganglion (in PNS)

Group of neuron cell bodies in the peripheral nervous system.

Nerve (in PNS)

group of axons in PNS

Sensory Function

Sensory receptors detect stimuli and send information to the CNS.

Sensory receptors

monitor changes in environment

Integrative function

process sensory information

Motor Function

Initiates action in muscle or gland.

Afferent Neurons (Sensory Divison)

Sensory neurons that carry information from the PNS to the CNS.

Motor Divison (Motor Neurons)

Motor neurons that carry information from the CNS to the PNS.

Somatic Division of PNS

Involves somatic sensory neurons and somatic motor neurons.

somatic sensory neurons

deliver info from sensory receptors in PNS to CNS

somatic motor neurons

deliver info from CNS to skeletal muscle

Autonomic Division of PNS

Includes autonomic sensory and motor neurons.

autonomic sensory neurons

deliver info from autonomic sensory receptors to CNS

autonomic motor neurons

deliver info from CNS to smooth muscle, cardiac muscle, glands

Sympathetic

responsible for the fight or flight response.

Parasympathetic

responsible for rest and digest functions.

enteric plexuses

networks of neurons in digestive tract

sensory neurons of enteric plexuses

monitor chemical changes in digestive tract and stretching of walls

motor neurons of enteroc plexsuses

control contraction of digestive tract smooth muscle

Neuron

Basic structural unit of the nervous system that conducts nerve impulses. Electrically excitable

Glial Cells

Support cells in the nervous system that protect and nourish neurons. Non-excitable

dendrites

recieve info

cell body (soma)

receives and integrates info. nucleus surrounded by cytoplasm

axon

sends info to effector cell

nissl bodies

rough er and gray

nerve fibers

processes that emerge from cell body and include dendrites; short, highly branched, and many. axons too

axon hillock

axon+ cell body come together

axoplasm

cytoplasm of axon

axolemma

cell membrane surrounding axon

telodendria

fine terminal extensions

synaptic knob

expanded regions at tips of teledendria

unipolar

single short process, branches like T.

functional divison :sensory

bipolar

2 processes- 1 dendrite, 1 axon

functional divison: sensory

multipolar

many dendrites, 1 axon

functional divison; motor

Synapse

Juncture between a neuron and another cell that allows for information exchange.

Electrical Synapse

Cells physically connected via gap junctions that pass electrical signals directly.

Chemical Synapse

Cells not physically connected that communicate via neurotransmitters.

Neurotransmitter

Chemical messengers produced by neurons to transmit information."},{