Ch 5 Nervous system 1 Flashcards
233-240
Makeup and function of nervous system
Composed of the brain , spinal cord, and peripheral nerves
Primary function to collect sensory information the internal and external enviornment
Neurons
Is the structural unit of the nervous system
Nerve cell
Is the same as a neuron
Nerve fibers
Are projections from the body of the nerve cell that carries nervous impulses
Dendrities
Connect with other neurons to receive information
Axon
Conducts impulses away from the cell body
Axon terminals
Distal ends of the axon
Synaptic bulb
Small sack at the end of the axon terminals that contain vesicles that store and release nerotransmitters
Nerotransmitters
Chemical that conducts a nerve signal across a synapse
Synapse
The junction where nerve signals jump from one nerve to another
Sensory neuron
Carries impulses from the sense organs to the brain
Motor neurons
Carries nerve impulses from the brain to the muscle/gland it controls
Interneurons
Carries impulses from one neuron to another
Nerves
Bundles of fibers held together by connective tissue that originate in the brain and spinal cord and distribute branches all over the body
Afferent nerve
Carry the impulses tword the spinal cord and brain
Efferent nerve
Carry impulses from the brain/spinal cord to the muscle/glands
Neurogila
hard nonneuronal cells in the brain and parochial nervous system that provide support and protection for the neurons
Neurogila: Astrocytes
Star shaped cells found in the CNS that structurally support the neurons
Neurogila: Oligodendrocytes
Found in the CNS, produce myelin that surrounds the axons in the brain and spinal cord
Neurogila: Schwann cells
Forms the Myelin that protects the axons of the PNS
Neurogila: MIcroglia
Small cells that function as phagocytes that remove cellular debris and dammaged nerve tissue from the CNS
Neurogila: Ependymal cells
Form epithelial-like membrane that lines certain structures of the brain and produces cerebral spinal fluid
Neurogila: Satellite cells
Forms structure called Ganglia in the PNS by surrounding dendrites and cell bodies to provide structural support and a medium of exchange between the nerve cells
Peripheral nervous system (PNS)
a network of nerves branching from the spinal cord, acts as the body’s communication pathway, relaying signals to the central nervous system (brain and spinal cord) and carrying instructions back to muscles and organs.
Central nervous system (CNS)
consists of the brain and spinal cord; responsible for processing information and initiating responses
Meninges
Fibrous connective tissue covering the CNS, consists of the Dura mater, Pia mater, Arachnoid mater
Dura mater
Outer most layer of the meninges
Pia mater
Inner most layer of the meninges
Arachnoid mater
Middle space of the meninges
Parts of the brain: Cerebrum
Larget portion of the brain, split into two sides; Responsable for speech, sensation, communication, memory, reasoning, will, and emotions.
Parts of the brain: Cerebellum
Smallest part of the brain; helps to maintain body balence, coordnates Volentary muscles, makes muscular movement smooth
Parts of the brain: Diencephalon
Main function- primary relay and processing center for sensory information and autonomic control
INCLUDE:
hypothalamus: governs the pituitary gland; regulative effect on autonomic system and the endocrine glands
thalamus: relay center for the brain
pineal: regulate the body’s circadian rhythm
pituitary glands: Secrete hormones to control other endocrine glands
Parts of the brain: Brain stem
Function: Relay and transmit impulses from one portion of the brain to another
INCLUDE-
Midbrain:Main nerve pathways connecting the cerebrum and the lower nervous system as well as certain visual and auditory reflexes
Pons: Relay nerve impulses between the cerebrum and medulla and from the cerebrum to the cerebellum
Medulla oblongata: Regulate movement of the heart and control vascoconstriction of arteries and the rate and depth of respiration
Autonomic nervous system
Part of the peripheral nervous system regulating the action of glands, smooth muscles and the heart
Somatic nervous system
Part of the peripheral nervous system consistes of nerves that connect to the CNS to the voluntary muscles and skin
Cranial nerves
12 pairs of nerves that emerge from the brain through openings in the base of the cranium
Number of pairs cranial nerves
12 pairs
Number of pairs spinal nerves
31 pairs
Cervical plexus
Consists of the four upper cervical nerves that supply the skin and control the movement of the head, neck, and sholder
Brachial plexus
Composed of four lower cervical nerves and the first pair of thoracic nerves that control arm movement
Lumbar plexus
Formed from the first four lumbar nerves
Sacral plexus
Formed from the fourth and fifth lumbar nerves and the first four sacral nerves
Sciatic nerve
Longest nerve in the body
Coccygenal plexus
Formed from portion of the fourth sacral nerves, the fifth sacral nerves, and the coccygeal nerve