Chapter 12 Nervous system

the nervous system contains

neurons and neuroglia

neurons

intercellular communication

Neuroglia

essentials survival functions of neurons

preserve structure of nervous tissue

The brain and spinal cord consist of

nervous tissue connective tissue and blood vessels

The brain and spinal cord receive sensory information’s from

inside and outside body

The brain and spinal cord functions to

process and coordinate sensory data

Brain spinal cord generates more commands to

control actives of peripheral organs (ex: skeletal muscles, glands, viscera)

Higher functions of the brain include

intelligence, memory, learning, and emotion.

The Peripheral nervous system includes all nervous tissue outside the

CNS, and ENS

Where does the Peripheral nervous system deliver sensory information to

the Central Nervous System

Where does the Peripheral Nervous System carries motor commands to

peripheral tissue

Bundles of axons with

connective tissues and blood vessels

Carry sensory

information and motor commands

How many sensory Cranial Nerves connect to the brain

12 pairs

How many spinal nerves attach to the spinal cord

31 pairs

Afferent division

carries sensory information

Afferent division carry receptors in the

peripheral tissues and organs to the CNS

Efferent division

carries motor commands

Efferent division from

CNS to muscles, glands, and adipose tissue

Divisions of the Nervous System are functional divisions of the

PNS

Receptors detect

changes respond to the stimuli

Receptors can be

neurons and specialized

Receptors may be

single cells or complex sensory organs (EG: eyes, ears)

Effectors target

organs that respond to motor commands

Examples of Effectors

skeletal, muscles, glands, viscera

Efferent divisions of

PNS

Somatic nervous system

controls skeletal muscle contractions

Somatic nervous system can be both

voluntary and involuntary (reflexes)

What do Automatic nervous system control

subconscious actions, contractions of smooth and cardiac muscle and glandular secretions

Sympathetic division

has stimulating effect (fight or flight response)

Parasympathetic

division has relaxing effect (rest and digest)

Nervous System

helps control the digestive system

What does the nervous system use, and which system is it common in

neurotransmitter common in the CNS

What else controls the Nervous System

the Autonomic nervous system

The basic functional units of the nervous system

Neurons

Send and receive signals

Neurons

Neurons generate

nerve impulses (also named action potential)

What are the function in the Neurons

communications, information processing, and control

Cell Body (Soma)

Large nucleus and nucleolus

Perikaryon

the cytoplasm

Mitochondria

produce energy, ATP

Synthesis proteins

R.E.R and ribosomes

Short and highly branched processes extending from cell body.

Dendrites

Dendric cells are made of

Dendritic spines

Dendrites receive information from other

neurons Afferent signal

What percent is the neuron surface area

80-90 percent

Single, long cytoplasmic process

Axon

Axon propagates

electrical signals making them (Action Potentials)

Cytoplasm of the axon

Axoplasm

Axoplasm contains

neurofibrils, neurotubles, enzymes and organelles

Dense areas of RER (Rough Endoplasmic Reticulum) and ribosomes in perikaryon

Nissel bodies

Nissel bodies make nervous tissue appear in

gray matter

Neurofilaments and neurotubules are similar to

filament and microtubules

Bundles of neurofilaments that provide support for dendrites and axon

Neurofibrils

Plasma membrane of the axon

Axolemma

What covers does the Axolemma cover

the axoplasm

base of axon

Initial segment

thick region that attaches initial segment to cell body

Axon hillock

–Which is the direction of the action potential (nerve impulse or electrical signal)?

A) Cell body>>>axon>>>Telodendria>>>>>axon terminal>>>Other cells

The structures of an Axon are

Collaterals, Telodendria, and Axton terminals

Collaterals

branches of the axon

telodendria

fine extensions of distal axon

axon terminals (synaptic terminals)

tips of telodendria

cell body and axon terminals

movement of materials

materials move along

neurotubles within axon

powered by

mitochondria, kinesin, and dynein

Anterograde transport

transport from the cell body to the terminal axon

Retrograde transport

rabies virus, varicella zoster

Anaxonic neuron

in brain and special senses

Bipolar neuron

found in special sense organs (sight, smell, hearing)

Unipolar neuron

most sensory neurons of PNS; Sensory ganglia (dorsal root ganglia)

Multipolar neuron

Common in the CNS all motor neurons that control skeletal muscles

Small, All cell processes look similar, found in brain and special sense organs

Anaxonic neurons

small and rare. one dendrite and one axon. found in special sense organs (sight, smell, hearing)

Bipolar neurons

Axon and dendrites are fused

Unipolar neurons (pseudo unipolar neurons)

Cell body to

one side

Most sensory neurons of

PNS

Sensory ganglia

(dorsal root ganglia)

Multipolar neurons

have one long axon and two or more dendrites

Multipolar neurons are common in the

CNS (Central Nervous System)

All motor neurons that control

skeletal muscles

Sensory neurons

receive information

Motor neurons

send motor command to effectors

Interneurons

in between sensatory and motor neurons

Sensory neurons

afferent neurons

Sensory neurons can be

unipolar

Cell bodies are grouped in the

sensory ganglia

Sensory neurons processes (afferent fibers) extend from sensory receptors to the

CNS (central nervous system)

Monitor external environment

Somatic sensory neurons

Visceral sensory neurons

Monitor internal environment

What are the types of sensory receptors

Interoceptors, Exteroceptors, and Proprioceptors

Interoceptors

Monitor internal systems (EG digestive, urinary)

Exteroceptors

monitor external environment (e.g. temperature)

Complex senses (e.g. sight smell, hearing

Monitor position and movement of skeletal muscles and joints

Proprioceptors

Carry instructions from CNS to peripheral effectors.

multiple neurons.

Via efferent fibers (axons)

Motor neurons (efferent neurons)

Somatic motor neurons of the SNS

innervate skeletal muscles

ANS (automatic Nervous System)

Visceral motor neurons