A&P Chapter 13 Flashcards
Brain Stem
- connects spinal cord to the brain
- consists of medulla oblongata, pons, and mid brain.
Medulla Oblongata
- most inferior portion of the brain stem
- gray matter organized into nuclei (reflex center)
- pyramids
- descending tracts involved in skeletal muscle.
- tracts crossover to other side
- olives: balance, coordination, adn inner ear sound.
Pons
- superior to the medulla oblongata-
- ascending and descending tracts
- pontine sleep center: REM sleep, actually recharges you
- Pontine respiratory center: respiratory movements.
Midbrain
- smallest region of brainstem
- superior colliculi (looks like a butt)
- reflex of head,eyes, and body toward stimuli.
- receive touch and auditory input
- inferior colliculi
- hearing and CNS auditory pathways
- red nuclei
- unconscious motor activities
Reticular formation
- loosely scattered nuclei in brain stem
- receives signals from axons that innervate face
- involved in cycles of activity
Cerebellum
- posterior to pons
- communicates with other regions of CNS
- superior peduncle: midbrain
- middle peduncle: pons
- inferior peduncle: medulla oblongata
- folia: ridges in cerebellar cortex
- purkinje cells: inhibitory neurons
Cerebellum-Flocculonodular lobe
balance and eye movement
Cerebellum- Vermis
posture, locomotion, and fine coordination ( helps to time things like swinging a bat)
Cerebellum- lateral hemispheres
- divided into primary fissure into anterior and posterior lobes
- planning, practicing, and learning complex movements
Diencephalon
- between brainstem and cerebrum
- consists of thalamus, subthalamus, epithalamus, and hypothalamus.
Thalamus
- largest part of diencephalon
- sensory relay center of the brain
- medial geniculate: auditory information
- lateral geniculate: visual information
- ventral posterior: sensory impulses
- dorsal tier: pain
- motor function: ventral anterior and ventral lateral nucleus
Thalamus
- influences mood
- anterior and medial nuclei: mood modification
- lateral dorsal nuclei: regulating emotions
- lateral posterior and pulvinar: sensory integration
Subthalamus
- inferior to thalamus
- ascending and descending tracts
- subthalamic nuclei :involved in controlling motor function.
Epithalamus
- superior and posterior thalamus
- consists of habenula and pineal gland
- habenula: responses to odor
- pineal gland; contolling onset of puberty
Hypothalamus
- regulates pituitary secretions
- stimulates sweating and shivering
- infundibulum: connects hypothalamus to pituitary
- mammilary bodies: responses to odor
- receives inputs from internal organs, tongue, limbic system, and eyes
- efferent fibers synapse with autonomic : regulates heart rate and digestion
Cerebrum
- largest portion of the brain
- logitudinal fissure: left and right hemispheres
- gyri: folds which increase surface area( grooves are sulki)
- hemispheres divided into lobes; named for skull bones
Frontal lobe
voluntary motor, motivation, aggression, smell, and mood
Parietal lobe
receiving and evaluating sensory info
occipital lobe
visual input
Temporal lobe
smell, hearing, and memory
Structures of cerebrum
lateral fissure: separates temporal lobe from rest of cerebrum
cerebral cortex: gray matter
cerebral medulla: white matter
Limbic system
- basic survival
- memory, reproduction(pheremones), and nutrition(hunger)
- interpretation of sensory inputs
- involved in emotion
Basal nuclei
- largest nuclei in the brain
- functionality related nuclei: located in cerebrum, diencephalon, and midbrain
- control of motor function
Cerebral medulla
- contains tracts that connect to CNS
- association fibers: connect areas within same hemisphere.
- commissural fibers: connects hemispheres; corpus callosum is the largest
- projection fibers: connect cerebrum to other parts of the brain
Meninges
connective tissue membranes
- Dura mater: superficial
- arachnoid mater
- pia mater: bound tightly to brain
Dura mater
superficial and tightly bound to internal periosteum
Arachnoid mater and subdural space
- thin, wispy layer
- Subdural space: between dura and arachnoid: only a small amount of serous fluid within
Pia mater and subarachnoid space
pia mater: thin, delicate C.T. membrane closely adhered to the brain: follows external contours.
subarachnoid space: contains web-like strands of arachnoid, blood vessels, and cerebrospinal fluid
Ventricles
- CNS forms as hollow tube
- lined by ependymal cells(produce cerebrospinal fluid)
- lateral ventricle: large cavity in cerebral hemisphere; fusion of 1st and 2nd ventricle
- third ventricle: center of diencepalon between thalamus halves
Intraventricular formina
lateral ventricles communicate with 3rd ventricle
fourth ventricle
base of cerebellum
cerebral aqueduct
third ventricle communication with fourth
Cerebrospinal fluid
- protective cushion around the CNS
- brain floats
- provides protection from rapid head movements
- provides some nutrients
- choroid plexus: ependymal cells, support tissue, blood vessels
- invaginations of pia mater
Brain blood supply
- brain has high metabolic rate
- requires 15-20% blood pumped by the heart
- interruptions can cause unconsciousness in seconds
- internal carotid arteries: blood reaches brain; anterior lateral of the neck.
Cranial nerves
- 12 pairs
- functions of sensory, somatic, and motor
Olfactory (I) and optic(II)
smell and vision; exclusively sensory
oculomotor (III)
eye and eyelid
Trochlear nerves (IV)
eye movement
Trigeminal (V)
mastication, middle ear, and throat
Abducens (VI)
eyeball movement
Facial (VII)
facial expressions, middle ear, and hyoid. Sense of taste for tongue.
Vestibulocochlear( VIII)
hearing and balance
Glossopharyngeal (IX)
pharynx and salivary glands, taste, sensory info from carotid arteries.
Vagus (X)
- soft palate, pharynx and larynx
- sensory from aortic arch
Accesory nerve(XI)
sternocledomastoid and trapezius
Hypoglossal (XIII)
tongue, thyrohyoid, geniohyoid.
VAgus
- vagus nerve innervates many internal organs
- vagus runs behind the liver
- brain shuts down innervations to lower limbs.
