-
CNS brain & spinal cord
integrative and control centers
-
PNS sensory and motor divisions
afferent and efferent; cranial nerves, spinal nerves
-
sensory:
sends info toward CNS afferent
-
external stimuli
towards brain and spinal cord
-
CNS is made up of these 2 things
-
the PNS is the ______ division
Efferent/motor division
-
PNS transmits______ from the _____ to ______
- impulses
- CNS
- effector organs
-
somatic or _______ nervous system
voluntary
-
somatic nervous system does what?
- conscious control of skeletal muscles
- sends info to skeletal muscles
-
autonomic or ______ nervous system
involuntary
-
autonomic nervous system does what?
regulates smooth muscle, cardiac muscle, and glands
-
two functional subdivisdions of autonomic nervous system
- sympathetic division
- parasympathetic division
-
visceral afferent fibers
conveys impulses from visceral organs to CNS
-
parasympathetic
“rest and digest”
-
sympathetic
“fight or flight”
-
what is the most important regulatory system?
nervous system
-
Nervous system function
Sensory:
info is gathered by the sensory receptors about internal and external changes
-
intergration
interpretation of sensory input
-
motor
activation of effector organs (muscles and glands) produce a responce
-
CNS integrates info it recieves from _____ and ______ _______
- internal stimuli
- external stimuli
-
CNS also coordinates :
activity
-
the brain, along with the spinal cord and network of nerves controls:
- 1 info flow throughout the body
- 2 voluntary actions such as walking
- 3 involuntary reactions such as breathing
-
the spinal cord begins at _________ and ends at ________
- begins = the foramen magnum
- ends = conus medulllaris at L1 vertebra
-
filum terminale
connects spinal cord to coccyx
-
2 funtions of spinal cord
- provides 2 way communication to and from the brain
- contains spinal reflex centers
-
3 structures of the spinal cord
- cervical bulge
- lumbar bulge
- conus medullaris
-
spinal nerves
- part of the peripheral nervous system.
- 31 pairs
-
cervical and lumbar enlargments
the nerves serving the upper and lower limbs enlarge here
-
cauda equina
the collection of nerve roots at the inferior end of the vertebral canal
-
spinal cord
cross sectional anatomy
2 lengthwise grooves divide cord into right and left halves.
-
what are the 2 lengthwise grooves divide cord into right and left halves.
- Ventral or anterior median fissure
- dorsal (posterior) median sulcus
-
gray commissure
connects the of gray matter encloses central canal
-
Dorsal (posterior) horns
interneurons that recieve somatic and visceral sensory input
-
ventral (anterior) horns
somatic motor neurons whose axons exit the cord via ventral roots
-
lateral horns
- remember! only located in thoracic and lumbar regions
- sympathetic neurons
-
dorsal root (spinal) ganglia
- contain cell bodies of sensory neurons
- send sensory input to dorsal horns
-
white matter mostly of
- ascending (sensory) tracts
- decending (motor) tracts
-
transverse tracts
- commissural fibers
- cross from one side to the other
-
white matter of the spinal cord arraged into
- columns (larger units)
- tracts (subunit of columns)
-
ascending tracts:
carry sensory signals up the spinal cord
-
descending tracts
descending tracts carry motor signals down the brain stem and spinal cord
-
brain is made up of 4 pricipal sections
- 1 diencephalon
- 2 brain stem
- 3 cerebrum
- 4 cerebellum
-
diencephelon has 3 paired structures list them
- thalamus
- hypothalamus
- epithalamus
-
diencephalon encloses which ventricle
third
-
the pituitary gland is also known as the _____ gland
master
-
hypothalamus
infundibulum:
stalk that connects to the pituitary gland
-
Hypothalamic function
- Autonomic control center for many
- visceral functions (e.g., blood pressure, rate and force of heartbeat, digestive tract motility)
- Center for emotional response: Involved in perception of pleasure, fear, and rage
- Regulates body temperature, food intake, water balance, and thirst
- Controls release of hormones by the anterior pituitary
- Produces posterior pituitary hormones
-
Thalamus
- 80% of diencephalon
- gateway to the cerebral cortex
- sorts,edits,and relays information
-
epithalamus
- Most dorsal portion of the diencephalon
- Pineal gland—extends from the posterior border and secretes melatonin
- Melatonin—helps regulate sleep-wake cycles and other biological rhythms
-
what is the specific order of the brain stem?
- midbrain
- pons
- medulla oblongata
- reticular formation & RAS
-
what does the brain stem control?
what is it associated with?
- Controls automatic behaviors necessary for survival
- Associated with 10 of the 12 pairs of cranial nerves
-
Diencephalon encapsulates which ventricle of the brain?
3rd
-
Mid Brain
- located between the diencephalon and the pons
- cerebral aqueduct
- channel between third and fourth ventrilcles
-
Mid Brain nuclei
Corpora quadrigemia :
domelike dorsal protrusions
-
Mid Brain nuclei
Superior colliculi
- top two protrusions of corpora quadrigemia
- visual reflex centers
-
Mid Brain nuclei
inferior colliculi
bottom two protrusions of corpora quadrigemia
-
Mid Brain nuclei
substantia nigra
produces the neurotransmitter dopamine
-
Pons
- with medulla oblongata controls breathing
- froms part of the anterior wall of the fourth ventrilcle
- maintains normal rhythm of breathing
-
Medulla oblongata
- controls breathing with Pons
- joins spinal cord at the foramen magnum
- contains a choroid plexus of the fourth ventricle
-
decesation or crossing over occurs in three places:
- spinal cord
- mudulla oblongata
- thalamus
-
Centers of medulla oblongata (4)
- autonomic reflex centers (heart rate, BP)
- cardio vascular center
- respiratory center
- additional centers for vommiting,hiccuping, swallowing, coughing, sneezing
-
riticular formation
- three broad columns along the length of the brain stem
- has far-flung axonal connections with the hypothalamus, thalamus, cerebral cortex, cerebellum, and spinal cord
-
Reticular formation RAS
- RAS : reticular activating system
- sends impulses to the cerebral cortex to keep it concous and alert
- filters out repetitive and weak stimuli
- severe injury results in perminent unconciousness (coma)
-
cerebrum
- largest part of the human brain
- associated with higher brain functions such as thought and action
- memory, cognition
-
Structure of cerebrum
divided into right and left _______
hemispheres are connected by ________
_______ in the corpus callosum allow two hemispheres to share info
cerebral cortex:
- hemispheres
- corpus callosum
- nerve tracts
- grey matter, the outer layer of the cerebrum
-
what is the lateralization of the cortical function?
division of labor between hemispheres
-
what is cerebral dominance
designates the hemisphere dominant for language
-
left hemishpere is associated with :
controls language, math, and logic
-
right hemisphere is associated with:
insight, visual spatial skills, intuition, and artistic skills
-
cerebral cortex or gray matter is made up of (2)
-
surface markings (3)
- gyri = ridges and folds
- sulci = shallow grooves
- fissures = deep grooves
-
what are the 5 lobes
- frontal
- parietal
- temporal
- occipital
- insula
-
surface markings of cerebral hemishperes
central sulcus:
- seperates the frontal and parietal lobes
- seperates the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe
-
surface markings of cerebral hemishperes
longitudinal fissure
seperates the two hemispheres
-
surface markings of cerebral hemishperes
transverse cerebral fissure
sepereates the cerebrum and the cerebellum
-
cerebral cortex
frontal lobes consist of
- precentral gyrus/primary motor cortex
- premotor cortex
- prefrontal cortex/anterior association area
- broca's area - language area
-
precentral gyrus/primary motor cortex
- executes voluntary movements
- allows conscious control of precise, skilled, voluntary movements
- the primary motor cortex on one side controls all moving parts on the contralateral side of the body.
-
premotor cortex
- anterior to the precentral gyrus
- selects voluntary movements, which are then executed by the primary motor cortex
- controls learned, repetitious, or patterened motor skills
- coordinates simultaneous or sequential actions
- involved in the planning of movements that depend on sensory feedback
-
Pre-frontal cortex /anterior association area
- most complicated cortical region
- involved with intellect, cognition, recall, personality, impulse control, reactivity to the surroundings and mood.
- contains working memory needed for judgment, reasoning, persistence, and conscience
- executive area for task managment
- solving complex, multitask problems, sequencing of activity, planning, abstract reasoning, and deviding attention.
-
broca's area
- anterior to the inferior region of the premotor area
- present in one hemisphere usually left
- a motor speech area that directs muscles of the tongue
- is active as one prepares to speak
- controls expressive language functions
-
Parietal Lobes
Postcentral gyrus/primary sensory (somatosensory) cortex
- In the postcentral gyri
- Receives sensory information from the skin, skeletal muscles, and joints
- Mediate proprioception (awareness of the position of body parts in space).
- Capable of spatial discrimination: identification of body region being stimulated
- Lesions of the anterior parietal lobe can cause difficulty recognizing objects by touch
-
Somatic Sensations Arise from Receptors Throughout the Body
- Detect touch, pressure, vibration, pain, awareness of body position and movements
- Send impulses to the primary somatosensory area of parietal lobe
- Somatosensory area processes the information and sends it to the primary motor area in the frontal lobe
-
Secondary sensory area/somatosensory association cortex
- Posterior to the primary somatosensory cortex
- Integrates sensory input from primary somatosensory cortex
- Determines size, texture, and relationship of parts of objects being felt
- Damage can affect the ability to recognize objects even though the objects can be felt.
-
temporal lobes
- Primary auditory cortex
- Secondary auditory cortex/auditory association area
- Wernicke’s area
-
Temporal lobes
primary auditory cortex
- Superior margin of the temporal lobes
- Interprets information from inner ear as pitch, loudness, and location
-
Temporal lobes
secondary auditory cortex/auditory association area
- Located posterior to the primary auditory cortex
- Stores memories of sounds and permits perception of sounds
-
Wernicke's area
- Located in the temporal lobe on the left side of the brain
- Involved in understanding written and spoken language
- Wernicke’s area is responsible for the comprehension of speech, whereas Broca’s area is related to the production of speech
-
occipital lobes
- primary visual cortex
- secondary visual cortex
-
occipital lobes
primary visual cortex
- extreme posterior tip of occipital lobe
- recieves visual information from the retinas
-
occipital lobes
Secondary visual cortex/visual association area
- Surrounds the primary visual cortex
- Uses past visual experiences to interpret visual stimuli (e.g., color, form, and movement)
-
cerebral cortex
insula
- gustatory cortex
- involved in the perception of taste
-
cerebrum
3 fibers of the cerebral medulla (white matter of the cerebrum)
- Association fibers
- commissural fibers
- projection fibers
-
Association Fibers
connect different parts of the same hemisphere
-
commissural fibers
- located in corpus callosum
- connect gray matter of the two hemispheres
-
projection fibers
connect the hemispheres with lower brain or spinal cord
-
cerebellum is the _____ ______ part of the brain.
second largest
-
functions of the cerebellum
- Subconsciously provides precise timing and appropriate patterns of skeletal muscle contraction
- Signals from proprioceptors and visual and equilibrium pathways continuously “inform” the cerebellum of the body’s position and momentum
- Helps to maintain balance
- Plays a role in nonmotor functions such as word association and puzzle solving
-
cerebellum also coordinates:
it also stores and replicates _____ __ _____ _______
- basic body movements
- sequences of skilled movements
-
Anatomy of cerebellum
two hemishperes connected by a vermis
-
each hemisphere of the cerebellum has three lobes:
- anterior
- posterior
- flocculonodular
-
Folia:
transversly oriented gyri
-
Arbor Vitae:
distinctive treelike pattern of the cerebellar white matter
-
cerebellum
flocculonodular node controls:
balance and eye movement
-
Blood brain barrier
helps maintain a ______ _______ for the brain.
stable enviroment
-
Blood brain barrier
seperates _______ from some blood bourne substances.
neurons
-
Blood brain barrier is selective in that it :
- Allows nutrients to move by facilitated diffusion
- Allows any fat-soluble substances to pass, including alcohol, nicotine, and anesthetics
-
ventricular system consists of:
- Lateral ventricles
- Third ventricle
- Fourth ventricle
- Choroid plexuses
-
Choriod Plexuses
- Produce CSF at a constant rate
- Hang from the roof of each ventricle
- Clusters of capillaries enclosed by pia mater and a layer of ependymal cells
- Ependymal cells use ion pumps to control the composition of the CSF and help cleanse CSF by removing wastes
-
Function of CSF - cerebrospinal fluid
- Gives buoyancy to the CNS organs
- Protects the CNS from blows and other trauma
- Nourishes the brain and carries chemical signals
-
what are the 3 layers of the Meninges from outer most to innermost layer?
- Dura Mater
- Arachnoid Mater
- Pia Mater
-
Dura Mater
- Strongest layer of meninges
- Two layers of fibrous connective tissue (around the brain) separate to form dural sinuses
-
Dural septa/folds limit excessive movement of the brain. What are the 3:
- Falx cerebri: in the longitudinal fissure
- Falx cerebelli: along the vermis of the cerebellum
- Tentorium cerebelli: horizontal dural fold over cerebellum and in the transverse fissure
-
Arachnoid Mater
______ layer with weblike extensions
Separated from the dura mater by the _________
Subarachnoid space contains ____ and _________
__________ protrude into the _________ and permit CSF reabsorption.
- Middle
- Subdural space
- CSF, Blood Vessels
- Arachnoid villi, Superior Saggital Sinus
-
Pia Layer
Layer of delicate vascularized connective tissue that clings tightly to the brain.
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