STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE CENTRAL NERVOUS SYSTEM Flashcards
how long is the spinal chord?
16-18 inches
the spinal chord extends from what to where
medulla oblongata to the L2
where is cerebrospinal fluid contained in the spine
central canal
the spinal cord has how many pairs of spinal nerves?
31
posterior root of the spine contains what type of axons?
sensory receptors(sending to CNS) afferent
anterior root of the spine contains what type of axons?
motor neurons (CNS to affectors) Efferent
the spinal cord has 2 enlargements what are they?
Cervical, lumbar
what is the function of white mater in the spinal cord?
has tracts that serve as highways for nerve impulses
Gray matter of the spinal cord
receives and integrates incoming and outgoing information and is a site for integration of reflexes.
Posterior horn
contains cell bodies and axons of interneurons as well as axons of incoming sensory neurons (afferent)
Anterior (ventral) gray horns
contain cell bodies of somatic motor neurons that provide impulses for contraction of muscles. (efferent)
Lateral gray horn is present only where?
thoracic and upper lumbar segments
Lateral gray horn contains?
cell bodies of autonomic motor neurons that regulate the cardiac muscle, smooth muscles, and glands
White Matter tracts?
Sensory tract (ascending) Motor (descending) tracts
Motor tracts
Consists of axons that conduct nerves impulses away from the brain
Sensory tract
consist of axons that conduct nerves impulses toward
the brain
what are the two levels of spinal reflexes?
Spinal reflex: Simple (reflex arc) (Patellar reflex)
Cranial reflex: Simple; occurs in the brainstem (Gag reflex)
how many spinal nerves are in the cervical
8
how many nerves are in the thoracic
12
how many nerves are in the lumbar
5
how many nerves are in the sacrum
5
how many nerves are in the coccyx
1
Sensory information goes through which root
Dorsal(posterior)
Motor information goes through which root?
anterior root
what is a dermatome?
an area of skin supplied by a single nerve
what is a group of axons arranged in bundles?
facicle
what are fascicles of a spinal nerve wrapped in?
perineurium
what is the superficial covering of a spinal nerve?
epineurium
what does the cervical plexus supplies and what nerves are in it?
posterior head, neck, upper part of the shoulder and the diaphragm
C1-C5
Brachial plexus supplies what?
contains what nerves?
upper limbs, some neck and shoulder muscles
C-5 to T-1
Lumbar plexus supplies what?
contains what nerves
Abdominal wall, external genitals and parts of the lower limbs
L-1 to L-4
Sacral plexus supplies what?
contains what?
Buttocks, perineum and most of lower limbs
L4-S4
The sciatic nerve contains what?
L4-S3
The brain contains what % of the bodies wt, but requires what % of the oxygen supply?
2% WT
20% O2
Brain neurons totally deprived of oxygen for ____ or more minutes may lead to permanent damage
four
_______ is a circulatory anastomosis that supplies blood to brain and surrounding structures; stems from the two internal carotid arteries.
Circle of Willis
Blood brain barrier does what?
protects the brain cells from harmful substances and pathogens
the blood brain barrier allows the passage of what?
lipid soluble materials such as O2, CO2, alcohol, anesthesia
what cells make up the blood brain barrier
astrocytes
what is a Clear, colorless liquid that cushions the brain, carries oxygen, glucose and other needed chemicals from the blood to neurons and removes waste.
Cerebrospinal Fluid
Cerebrospinal Fluid circulates through _____ around the spinal cord central canal, and through cavities in the brain called ____
subarachnoid space
ventricles
CSF is slowly reabsorbed into the blood through what?
arachnoid villi
What are the major parts of the brain?
Brain stem
diencephalon
cerebellum
cerebrum
what are the parts of the brain stem?
medulla oblongata
pons
midbrain
What are the parts of the diencephalon
thalamus
hypothalamus
pineal gland
what does cerebellum mean and what is its functions?
Little brain
balance and equilibrium for coordination
What forms the inferior part of the brain stem; a continuation of spinal cord
Medulla Oblongata
What are the functions of the Medulla Oblongata
regulates the rate and force of the heart and the diameter of the vessels
regulates breathing
what cranial nerves the the Medulla Oblongata associated with?
cranial nerves VIII-XII
what is the “Bridge” which connects the medulla to the midbrain and above
Pons
what Contains ascending (sensory) and descending (motor) tracts?
Pons
the pons connects what parts of the brain?
right and left…..
Pons is associated with what cranial nerves?
5, 6, 7 and 8
what connects the pons to the diencephalon
Midbrain
what is Substantia nigra
Loss of these neurons related to Parkinson disease
what is Cerebral peduncles
Large tracts that contain axons of motor neurons from cerebrum to rest of brainstem and spinal cord
what is involved in in scanning eye movement and responses to visual
stimuli
Superior colliculi
what does the response to auditory input and startle reflex
Inferior colliculi
what are the tree major regions of the diencephalon
thalamus
hypothalamus
pineal gland
Functions of what part of the diencephalon
1) Major sensory relay center
2) Contributes to motor functions
3) Plays role in consciousness
Thalamus
Functions of what part of the diencephalon
1) Lies inferior to thalamus and superior to the pituitary gland; important for
homeostasis
2) Control of pituitary and hormone production
3) Control and integration of the ANS
4) Regulation of emotional and behavior patterns
5) Regulation of eating and drinking
6) Control of body temperature
7) Regulation of circadian rhythms, sleep and awakening patterns
Hypothalamus
what Secretes melatonin which promotes sleepiness and contributes to setting the body’s biological clock
Pineal Gland
the cerebellum is attached to the brain stem by what?
cerebella peduncles
what Divides the cerebrum into right and left cerebral hemispheres
Longitudinal Fissure
Broad band of white matter containing axons that connects the right and left spheres internally
Corpus Callosum
what are the layers of the cerebrum
Cortex-superficial gray matter
white matter- myelinated and unmyelinated axons coms between hemispheres via corpus callosum
basal ganglia- Assist in motor control, emotions, behavior, executive function
what are the four lobes of the hemisphere
frontal, parietal, temporal, occipital
Central sulcus separates___ and ___
frontal and parietal
Precentral gyrus anterior to the central sulcus is ___
Primary motor area
Postcentral gyrus posterior to the central sulcus is?
Primary somatosensory area
Primary visual area
Occipital lobe
Primary auditory area
Temporal lobe
Primary gustatory (taste) area
Base of postcentral gyrus
Primary olfactory (smell) area:
Medial aspect of temporal lobe
Primary motor area
Precentral gyrus of the frontal lobe
Each region of the frontal lobe controls voluntary contractions of specific muscles on the ___ side of the body
opposite
Association areas do what
complex integration: memory, emotion, reasoning, judgment
Somatosensory association area
Integrates and interprets somatic sensations: storage of memories of past
sensory experiences
located Posterior to primary somatosensory area
Premotor area does what
Generates nerve impulses causing a specific group of muscles to contract in a specific sequence
what is Called “emotional brain”: plays primary role in pain, pleasure, anger, affection and in
behavior
limbic system
the structure of the limbic system contains what?
inner border of cerebrum and floor of diencephalon
what hemisphere is more involved with:
spoken and written language, numerical and scientific skills, and reasoning
Left
what hemisphere is more involved with:
spatial and pattern recognition, emotional content of language, generating images of sight, sound, taste, and smell
right
