Chapter 5 System 5 Nervous System Flashcards
Nerve fibers
Projections from the body of the nerve cell that carry nervous impulses
Dendrites
Connect with other neurons to receive information
Axon
Conducts impulses away from the cell body
Synapse
The junction where nerve signals jump from one nerve to another
Neurotransmitter
Is a chemical that sends a nerve signal across a synapse
Sensory neuron
Carries impulses from sense organs to the brain
Motor neuron
Carries nerve impulses from the brain to the effectors
Interneuron
Carries impulses from one neuron to another
Myelin sheath
Covers the axons of most nerves.
Made of fatty Schwann cells.
Insulates the nerve and aids in the conduction of the nerve impulse.
Neurons have the ability to react to certain stimuli (____) and to transmit an impulse generated by that stimulus over a distance or to another neuron (____).
Irritability
Conduct ability
Functionally, what are the three types of neurons?
Sensory / afferent neurons
Motor / efferent neurons
Interneurons / internuncial neurons
Sensory / afferent neurons
Sensations of touch, cold, heat, sight, hearing, taste, or pain are carried as impulses to the brain
Motor / efferent neuron
Carry nerve impulses from the brain to the effectors (the muscles or glands they control).
Interneurons / internuncial neurons
Located in the brain and spinal cord.
Carries impulses from one neuron to another.
Transmit and direct impulses from one place in the spinal cord or brain to another
Nerves
Are bundles of fibers held together by connective tissue that originate in the brain and spinal cord and distribute branches all over the body
Afferent nerves
Carry impulses toward the spinal cord or brain
Central nervous system
Consists of the brain and spinal cord
Meninges
A special connective tissue membrane that covers the CNS incased by bone
Meningitis
Is an acute inflammation of the pia mater and arachnoid mater around the brain and spinal cord
The three layers to meninges
Dura mater -outer -tough mother
Arachnoid mater -middle -spider layer
Pia mater - innermost -delicate mother
The primary function of the nervous system is to…
Collect a multitude of sensory information;
Process, interpret, and integrate that information;
Initiate appropriate responses throughout the body
The nervous system is composed of…
the brain, spinal cord, and peripheral nerves
Cerebrospinal fluid
Flows through and around the brain and spinal cord to nourish and protect them.
Main function is to protect the CNS by acting as a shock absorber for the delicate tissue
A clear fluid derived from the blood and secreted into the inner cavities or ventricles of the brain
The brain
The principal nerve center
Body’s largest and most complex nerve tissue
Containing in excess of 10 billion neurons and innumerable nerve fibers
Located in and protected by the cranium
Controls sensations, muscles, glandular activity, power to think and feel emotion
The brain includes… (4)
- Cerebrum
- Cerebellum
- Diencephalon
- Brain stem
Cerebrum
Largest portion, making up the front and top of the brain
Mental activity; speech, sensations, communication, memory, reasoning, will, emotions
Divided by a central fissure into left and right cerebral hemispheres.
Which is connected by bundles of nerve fibers called the corpus callosum. Provides communication between left and right hemispheres
The functions of the nervous system (4)
- To rule the body by controlling all visible and invisible activities
- To control human thought and conduct
- To govern all internal and external movements of the body
- To give the power to see, hear, move, talk, feel, think, and remember
Neuron / nerve cell
Is the structural unit of the nervous system
Cerebellum
Smaller part of the brain
Located below the cerebrum and at the back of the cranium
Helps to maintain body balance, coordinates voluntary muscles, makes muscular movement smooth and graceful
Diencephalon
Includes the hypothalamus, thalamus, and pineal and pituitary glands
Located in the center of the brain
The pituitary gland is considered to be the master gland because it’s hormones control other endocrine glands
Pituitary gland
Considered to be the master gland because it’s hormones control other endocrine glands
Located at the base of the brain in the sella turcica of the sphenoid bone
Brain stem
Has three parts; midbrain, the pons, and the medulla oblongata
these contain intricate masses of nerve fibers that relay and transmit impulses from one portion of the brain to another
Midbrain; contains the main nerve pathways connecting the cerebrum with the lower nervous system
The pons; between midbrain and medulla oblongata. relays nerve impulses between cerebrum - medulla and cerebrum - cerebellum
Medulla; is an enlarged continuation of the spinal cord that extends from the foramen magnum to the pons and connects the brain to the spinal cord. Regulates movement of the heart and controls vasoconstriction of the arteries, also the depth and rate of respiration
Spinal cord
Extends downward from the brain and is housed in and protected by the vertebral column
Consists of 31 segments
Peripheral nervous system
Consists of all the nerves that connect the CNS to the rest of the body
Autonomic nervous system
Regulates the action of glands, smooth muscles, and the heart
Somatic nervous system
Consists of the nerves that connect 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
Cervical plexus
Consists of the four upper cervical nerves that supply the skin and control the movement of the head, neck, and shoulders