Brain Quiz Flashcards
4 parts of the brain
Cerebrum
Diencephalon
Brain Stem
Cerebellum
Cerebrum
2 hemispheres
83% of total brain mass
Contains 5 Lobes: formed by deeper sulci
Each Hemisphere Contains 3 Basic Regions
3 Regions of cerebral hemisphere
Cortex
White Matter
Basal Nuclei
Cerebral Cortex
- 2-4 mm thick, superficial layer
2. Only Gray Matter
Cerebral cortex place for:
Place for: Perception, Communication, Memory, Understanding, Initiating voluntary movements
Cerebral cortex functional areas:
Functional Areas…that work together
A. Motor
B. Sensory
C. Association
Cerebral White Matter
- Deep to Cortex
- Provides communication within cerebrum
- Corpus Callosum
connects hemispheres
Basal Nuclei
- a.k.a. basal ganglia
2. Learning of importance (arm movement in walking)
Sulci:
shallow grooves
Gyri:
elevated ridges
Fissures:
deeper grooves (bet. L&R)
Diencephalon
- Thalamus
- Hypothalamus
- Epithalamus
Thalamus:
“relay center”
Hypothalamus
a. influences blood pressure, heart rate, breathing, eye pupil size, etc.
b. contains body’s thermostat
c. reg. feelings of hunger, satiety and thirst
d. regulate sleep patterns
e. produces some hormones
f. emotions, “heart” of the limbic system
Limbic System
If memory is associated with some emotion more likely to keep “long-term”
-Long-term potentiation (LTP)
is a process in which synapses are strengthened. (Repetition for frontal lobe -> incorporate into LTM)
Epithalamus
pineal gland: secretes melatonin
Brain Stem
3 Anatomical Parts
- Midbrain
- Pons
- Medulla Oblongata
Midbrain
a. cerebral peduncles hold up cerebrum
b. visual & auditory reflex centers
(startle reflex)
c. part of reticular formation (RAS)
1) sensory input filter 2) consciousness
Pons:
“relay center”
Medulla Oblongata
a. connects w/ spinal cord
b. decussation of the pyramids: crossover
c. Autonomic reflex center & homeostasis
1) cardiac & vasomotor center
2) respiratory center
3) centers for vomiting, hiccuping, swallowing, coughing, & sneezing
Cerebellum
(our “Autopilot”)
- 11% of brain
- interprets inputs for cerebrum,
brainstem, & sensory receptors - coordinated movement
Protection of the Brain
- Cranium
- Meninges
Meninges
- dura mater
subdural space - arachnoid mater
subarachnoid space has CSF - pia mater
Cerebrospinal Fluid (CSF)
- Watery solution similar to blood plasma but
a. less protein
b. different ion [ ]s than plasma
Cerebrospinal Fluid (CSF) Functions
Functions:
a. Protection: forms a liquid cushion
b. Food for brain
c. Carry chemical signals
Cerebrospinal Fluid (CSF) Made by...
Made by Choroid Plexus
a. Capillary clusters
b. Found along roof of ventricles
c. Ion pumps
Ventricles
Filled with CSF and lined by ependymal cells
I. Olfactory:
Sensory
Smell
II. Optic:
(Sensory)
Sight
III. Oculomotor:
(Primarily Motor)
Raise eyelids, focus lenses, move eyes
IV. Trochlear:
(Primarily Motor)
move eyes
Cranial Nerve I: Olfactory
• Arises from the olfactory epithelium
• Passes through the cribriform plate of the ethmoid bone
• Fibers run through the olfactory bulb and terminate in the primary olfactory cortex
• Functions solely by carrying afferent impulses for the sense of smell
Cranial Nerve II: Optic
• Arises from the retina of the eye
• Optic nerves pass through the optic canals and converge at the optic chiasm
• They continue to the thalamus where they synapse
• From there, the optic radiation fibers run to the visual cortex
• Functions solely by carrying afferent impulses for vision
Cranial Nerve III: Oculomotor
• Fibers extend from the ventral midbrain, pass through the superior orbital fissure, and go to the extrinsic eye muscles
• Functions in raising the eyelid, directing the eyeball, constricting the iris, and controlling lens shape
• Parasympathetic cell bodies are in the ciliary ganglia
Cranial Nerve IV: Trochlear
• Fibers emerge from the dorsal midbrain and enter the orbits via the superior orbital fissures; innervate the superior oblique muscle
• Primarily a motor nerve that directs the eyeball
V. Trigeminal:
(Sensory & Motor)
facial sensation, mastication
VI. Abducens:
(Primarily Motor)
lateral eye movement
VII. Facial:
(Sensory & Motor)
taste, facial expressions, tears, saliva
VIII. Vestibulocochlear:
(Sensory) (a.k.a. Auditory)
hearing, equilibrium
Cranial Nerve VI: Abducens
• Fibers leave the inferior pons and enter the orbit via the superior orbital fissure
• Primarily a motor nerve innervating the lateral rectus muscle
Cranial Nerve VII: Facial
• Fibers leave the pons, travel through the internal acoustic meatus, and emerge through the stylomastoid foramen to the lateral aspect of the face
• Mixed nerve with five major branches
• Motor functions include facial expression, and the transmittal of autonomic impulses to lacrimal and salivary glands
• Sensory function is taste from the anterior two-thirds of the tongue
Cranial Nerve VIII: Vestibulocochlear
• Fibers arise from the hearing and equilibrium apparatus of the inner ear, pass through the internal acoustic meatus, and enter the brainstem at the pons-medulla border
• Two divisions – cochlear (hearing) and vestibular (balance)
• Functions are solely sensory – equilibrium and hearing
IX. Glossopharyngeal:
(Sensory & Motor)
pharynx, tonsils, tongue, swallowing
X. Vagus:
(Sensory & Motor)
speech, swallowing, thorax & abdomen
XI. Accessory:
(Primarily Motor) (a.k.a. Spinal Accessory)
thorax, abdomen, larynx, neck, back
XII. Hypoglossal:
(Primarily Motor)
tongue
Cranial Nerve IX: Glossopharyngeal
• Fibers emerge from the medulla, leave the skull via the jugular foramen, and run to the throat
• Nerve IX is a mixed nerve with motor and sensory functions
• Motor – innervates part of the tongue and pharynx, and provides motor fibers to the parotid salivary gland
• Sensory – fibers conduct taste and general sensory impulses from the tongue and pharynx
Cranial Nerve X: Vagus
• The only cranial nerve that extends beyond the
head and neck
• Fibers emerge from the medulla via the jugular foramen
• The vagus is a mixed nerve
• Most motor fibers are parasympathetic fibers to the heart, lungs, and visceral organs
• Its sensory function is in taste
Cranial Nerve XI: Accessory
• Formed from a cranial root emerging from the medulla and a spinal root arising from the superior region of the spinal cord
• The spinal root passes upward into the cranium via the foramen magnum
• The accessory nerve leaves the cranium via the jugular foramen
• Primarily a motor nerve
– Supplies fibers to the larynx, pharynx, and soft palate
– Innervates the trapezius and sternocleidomastoid, which move the head and neck
Cranial Nerve XII: Hypoglossal
• Fibers arise from the medulla and exit the skull via the hypoglossal canal
• Innervates both extrinsic and intrinsic muscles of the tongue, which contribute to swallowing and speech
Brain Functions
- Interpret sensory impulses
- Initiate muscular movement
- Memory, Reasoning, Personality, Learning, Problem-Solving
- Maintain Homeostasis
- Coordinate muscle activity and posture
- Regulate Breathing, Heart Rate, and Blood Pressure; Some Reflexes