NERVOUS SYSTEM

Nervous system !!!

The nervous system begins pre-natally…

It eventually develops into the spinal chord with a specialized extension, the brainstem

The posterior portion of brain stem develops the more specialized cerebellum, and the anteriorDevelops the cerebral hemispheres

THE CENTRAL NERVOUS

SYTEM Comprises two parts: the brain and spinal chordEncased in bone for protection. In addition, Cerebrospinal fluid circulates inside and around the brain for additional protection

Brain – the organ that directly controls our thoughts,

emotions and motivations.

Spinal cord – a series of interconnected neurons Extending from the brain to the center of the back.It carries information to and from the brain

the two directional communication in the nervous system involves two different kinds of nerves and neurons….. Receptors – are

structures designed to receive

sensory information from

the outlying nerves of the

body and transmit that

information back to the brain thru the spinal

chord

Effectors – transmit motor information about how the nody should act in response to the information it receives. Usually, this information comes from the brain.

The Peripheral Nervous SystemComprises all of the nerve cells except those of the brain and the spinal cord.The primary job of the PNS is to relay information between the CNS and the receptorsAnd effectors lying outside the CNS.

The PNS connects with the receptors in both our external sensory organs and our Internal body parts.it connects with the

effectors that produce movement, speech and so on.

The PNS comprises of two main parts:

Autonomic nervous system – controls movement of our non skeletal muscles (heart and

smooth muscles). The smooth muscles include those of the blood vessels and the internal body organs

the Autonomic system is divided into

two parts…..

Sympathetic nervous system - is concerned primarily with ‘catabolism,’ the process by which your body captures stores and uses energy and materials from food and eliminate wastesParasympathetic nervous system –

concerned with ‘anabolism,’ the process

that stores energy in the body.

These two systems tend to work in tandem….

Somatic nervous system – controls quick and conscious movement of skeletal muscles. these muscles are attached directly to the bone and allow us to move. We have voluntary control over the muscles served by the somatic system

T h e b r a i nStructures and

functions

Forebrain-Located toward the top and front of the brain - comprised of two parts: the telencephalon and diencephalon

Telencephalon:

- three parts1~ the cerebral cortex (outer

layer of cerebral hemisphere) plays vital role in our thinking

2~ the basal ganglia - a collection of nerves crucial to motor functions

3~ the limbic system - imp. to emotion, motivation and learning. Comprises of3 interconnected cerebral structures

Diencephalon- between the telencephalon and

midbrain - comprises the thalamus and hypothalamus

Thalamus- relays incoming sensory information thru projection fiber

to the appropriate region in the

cortex

Hypothalamus- involved in water balance in tissues and bloodstreams. It controls much of the autonomic

nervous system and endocrine system

- involved in temperature regulation.

interacts with and is sometimes viewed as part of the limbic system. Therefore in involved in behavior related to survival : fighting, feeding,

fleeing, mating.

hypothalamus

the main source of control for visual and auditory information. The reticular activating system of the Midbrain regulates state of consciousness, including sleep, wakefulnessArousal, and attention, as well as breathing and heartbeat

Midbrain

HindbrainMost rearward

portion of the brain

1.Medulla oblongata-

part of the reticular

activating system helps control heartbeat, breathing, swallowing, digestion

2. pons- serve as a kind of relay station for signals passing from one part of the brain to another.

3. cerebellum- involved in bodily coordination, balance, and muscle tone.

fin