Chp. 12 Nervous System Flashcards
What is the function of the Nervous System?
coordinates and controls body functions; receives sensory input, makes decisions, and then orders body responses
What are the structures( and roles of them) of the
nervous system?
Brain: coordinates body functions
Nerves: Transmit messages to and from the central nervous system
Spinal Cord: Transmit messages to and from the brain
How does the nervous system coordinate all activities of the body?
Receives information from both external and internal sensory receptors which goes into the CNS and gets processed. motor messages exit the nervous system carrying commands to muscles and glands to match the needs of the body
What is the Nervous System split into and what is in the two systems?
Central Nervous System: Brain & Spinal Cord
Peripheral Nervous System: Cranial and Spinal Nerves, ANS, and somatic nerves
What are the two types of nerves in the PNS (has to do with function)?
Sensory nerves: carry the information to the central nervous system
Motor nerves: carry commands away from the central nervous system
What are the two basic types of cells that the Nervous Tissue consists of?
Neurons and Neurologlial cells
What are neurons and what is their function?
Individual nerve cells; capable of conducting electrical impulses in response to a stimulus
What are the 3 basic parts of a neuron?
dendrites, a nerve cell body, and an axon
What are dendrites?
highly branched projections that receive impulses
What is a nerve cell body (soma)?
contains the nucleus and many of the other organelles of the cell
What is an Axon?
projection from the nerve cell body that conducts teh electrical imulse towards its destination
What is a synapse?
the point at which the axon of one neuron meets the dendrite of the next neuron
What is a synaptic cleft?
gap between two neurons; electric impulses cannot pass directly across it
What are neurotransmitters?
helps the electric impulses get across the synaptic cleft
What are neuroglial cells?
has a different support function for the neurons such as producing myelin; do not conduct electrical impulses
What is myelin
a fatty substance that acts as insulation for many axons so they conduct electrical impulses faster
What is the function of the CNS?
Receives impulse all over body, process the information, and then respond with action
What are the two types of matter the CNS contains and describe them?
Gray Matter: comprised of unsheathed or uncovered cell bodies and dendrites
White Matter: myelinated nerve fibers
What are nerve tracts?
bundles of nerve fibers interconnecting different parts of the central nervous system
What is the brain the center for?
Thought, memory, judgement, and emotions
How many sections of the brain are there and what are they?
4 : Cerebrum, Cerebellum, Diencephalon, and Brain Stem
What is the function of the cerebrum?
Processes thoughts, judgement, memory, problem solving & language
What are the parts of the cerebrum?
Cerebral cortex, Gyri, Sulci, Cerebral Hemispheres (Frontal Lobe, Parietal Lobe, Occipital lobe, and Temporal Lobe)
What is the cerebral cortex?
outer layer of the cerebrum, which is composed of folds of gray matter
What is the Gyri?
elevated portions of the cerebrum
What is the sulci?
gyri are separated by fissures or valleys
What are the cerebral hemispheres?
erebrum is divided into right and left halves; each hemisphere has 4 lobes
What are the 4 lobes of the cerebral hemispheres?
Frontal lobe, Parietal lobe, Occipital lobe, and Temporal lobe
Frontal lobe
most anterior portion of the cerebrum; controls motor function, personality and speech
Parietal Lobe
Most superior portion of the cerebruml receives and interprets nerve impulses from sensory receptors and inereprets language
Occipital Lobe
Most posterior portion of the cerebrum; controls vision
Temporal Lobe
Left and right lateral portion of the cerebrum; controls hearing and smell
What does the Diencephalon contain?
Thalamus and Hypothalamus
What is the function of the Thalamus?
composed of gray matter and acts as a center for relaying impulses from the eyes, ears and skin to the cerebrum; controls pain perception
What are the functions of the Hypothalamus
controls body temperature, appetite, sleep, sexual dseire, and emotuons; responsible for controlling the autonomoic nervous system, cardiovascular system, digestive system, and the release of hormones from the pituitary gland
What is the Cerebellum and where is it located?
Second largest portion of the brain; located beneath the posterior part of the cerebrum
What are the functions of the cerebellum?
Aids in coordinating voluntary body movements, and maintaining balance and equilibrium; refines muscle movement initiated in the cerebrum
What does the Brain Stem contain (3)?
Midbrain, pons, and medulla oblongata
What is the function of the Midbrain?
acts as a pathway for impulses to be conducted between the brain and the spinal cord
What is the function fo the Pons?
bridge; connects the cerebellum to the rest of the brain
What is the Medulla Oblongata?
most inferior portion fo the brain; it connects the brain to the spinal cord; contains the centers that control respiration, heart rate, temperature and blood pressure; the site where nerve tracts cross one side of the brain to control functions and movement on the other side of the body (right side= left side of the body, left side= right side of the body)
What are Ventricles?
Four interconnected cavities
Where are the Ventricles found?
In each of the cerebral hemispheres, in the thalamus, and in front of the cerebellum
What does the ventricles contain and what is it?
Contains Cerebrospinal fluid: watery, clear fluid that provides protection from shock or sudden motion to the brain and spinal cord
What is the spinal cord?
A column of nervous tissue extending from the medulla oblongata of the brain down to the level of the second lumbar vertebra within the vertebral column
What is the function of the spinal cord?
Provides a pathway for impulses traveling to and from the brain
What is the spinal cavity of vertebral canal?
33 vertebrae of the backbone line up to form a continuous canal for the spinal cord
What is found in the spinal cord?
CSF, gray matter, and myelinated white matter
Where is CSF found in the spinal cord?
Flows down the center of the spinal cord within the central canal
What is gray matter?
Inner core of the spinal cord consists of cell bodies and dendrites of peripheral nerves
What is Myelinated White matter?
the outer portion of the spinal cord: either ascending tracts and descending tracts
What are ascending tracts?
carrying sensory information up to the brain
What are descending tracts?
carrying motor commands down from the brain to a peripheral nerve
What are the meninges?
Three layers of connective tiussue membranes surrounding the brain and spinal cord
What are the layers of the meninges?
Dura Mater, Subdural space, Arachnoid Layer, Subarachnoid space, and Pia Mater
Describe the Dura Mater
tough mother; it forms a tough, fibrous sac around the central nervous system
What is the Subdural space?
actual space between the dura mater and arachnoid layers
What is the Arachnoid Layer?
meaning spiderlike; it is a thin, delicate layer attached to the pia mater by weblike filaments
What is the Subarachnoid Space?
space between the arachnoid layer and the pia mater; it contains cerebrospinal fluid that cushions the brain from the outside
Pia Mater
meaning soft mother; it is the innermost membrane layer and is applied directly to the surface of the brain and spinal cord
Nerve
a group or bundle of axon fibers located outside the CNS that carries messages between the CNS and various parts of the body
What are the two types of nerves?
Cranial nerves and spinal nerves
What are cranial nerves?
arise from the brain, mainly at the medulla oblogata
12
What are spinal nerves?
split off from the spinal cord, and one pair (a left and a righT0 exits between beach piar of vertebrae
31
What is a nerve root?
the point where either type of nerve is attached to the CNS
What are Afferent Neurons?
carry sensory information from a sensory receptor to the CNS (Sensory Neurons)
What do Efferent neurons?
carry activity instructions form the CNS to muscles or glands out in the body
Motor neurons
Ganglion
the nerves cell bodies of the neurons forming the nerve area that are grouped together in a knot-like mass
What are the parts of the PNS?
Autonomic Nervous System, Somatic Nerves, Cranial Nerves, and Spinal Nerves
What is the function of the Autonomic Nervous System?
Involved with the control of involuntary or unconscious bodily functions
What is an example of what the ANS does?
Increase or decrease the activity of smooth muscles found in viscera and blood vessels, cardiac muscle, and glands
What are the two branches the Autonomic Nervous system is divided into?
Sympathetic Branch and Parasympathetic branch
What type of reaction does the sympathtic branch give and when?
Fight or flight reaction during times of stress and crisis
What does the Sympathtic Branch do to the body during in time of stress and crisis?
increase heart rate, dilate airways, increase blood pressure, inhibit(prevent) digestion, and stimulate the production of adrenaline
What type of reaction does the Parasympathtic branch give?
Opposite of Sympathetic branch; rest and digest reaction:
What type of reactions does the body give? (parasympathtic branch)
Heart rate to slow down, lower blood pressure, and stimulate digestion
What does the Somatic Nerves do?
Serve the skin and skeletal muscles and are mainly involved with the conscious and voluntary activities of the body
What are the functions of the Somatic Nerves?
Sensory receptors found in the dermis layer of the skin uses somatic nerves to send their information, such as touch, temperature, pressure, and pain, to the brain.
Carries motor commands to skeletal muscles
