Brain Flashcards
What determines intelligence?
The number of synapses (approx 86 billion)
Not the brain
Grooves between gyri
Sucli
Deep sucli
Fissures
Skull limits brain size, so our brain (cortex) is folded (____) to make room for more neurons
Gyri
The cerebrum is made up of two _____
Hemispheres
Big suclus between hemispheres
Longitudinal fissure
In addition to the skull, the brain is supported and protected by connective tissue layers called_____
meninges
Deep to superficial meninges:
Pia mater, arachnoid and dura mater
Dura mater has 2 layers
Periosteal-superficial
Meningeal-deep
All 3 meninges cover the ____ AND the _____
Brain, spinal cord
Bone of skull/vertebrae and dura mater may be separated by a potential space ______
epidural space
Contents of epidural space
arteries and veins that nourish the meninges and bones
Dural septa that divides the cerebrum into L and R hemispheres
Falx cerebri
Dural septa that tents over the cerebellum, separates cerebrum from cerebellum
Tentorium cerebelli
Dural septa that divides the cerebellum into L and R sides
Falx cerebelli
Partitions of the dura form the _____
dural venous sinuses
All blood leaving the brain goes to _____
dural venous sinuses
Descending veins where blood goes after the dural venous sinuses
Superior sagittal sinus
Straight sinus
Transverse Sinus
Spaces in the brain
ventricles
The ventricles are continuous with each other, and with the ______
central canal of the spinal cord
Ventricles and central canal are filled with _____
cerebrospinal fluid (CSF)
Ventricles are lined with_____
ependymal cells
Four brain ventricles:
2 lateral ventricles (medial portion of cerebrum)
Third ventricle in the diencephalon
Fourth ventricle between pons and cerebellum
In the third ventricle in the diencephalon, lateral ventricles are connected to the third ventricle by the_______
interventricular foramen
Third ventricle in the diencephalon, third ventricle is connected to the fourth ventricle by the _______
cerebral aqueduct
Fourth ventricle between pons and cerebellum empties into _____
central canal of spinal cord
Functions of the cerebral spinal fluid
Buoyancy
Protection: liquid cushion to protect neurons from sudden movements
Environmental Stability: provides nutrients, eliminates wastes
____supports 95% of brain weight, prevents brain from being crushed under its own weight.
CSF
CSF is made by the ______within each ventricle
choroid plexus
_______ filter fluid out of the blood and secrete it in the form of CSF
Ependymal cells
- CSF is secreted by ____ in each ____.
- CSF flows through ____into ____.
- ______ in third ventricle adds more CSF.
- CSF flows down _____to fourth ventricle.
- _____ in fourth ventricle adds more ___.
- CSF flows out two ___and one ____.
- CSF fills ____ and bathes external surfaces of ___ and _____.
- At arachnoid granulations, CSF is reabsorbed into _____.
- choroid plexus, lateral ventricle
- interventricular foramina, third ventricle
- Choroid plexus
- cerebral aqueduct
- Choroid plexus, CSF
- lateral apertures, median aperture
- subarachnoid space, brain, spinal cord
- venous blood of dural venous sinuses
The _____make about 500 mL of CSF a day
choroid plexi
BUT volume of CSF is usually _____
100-160 mL
CSF is absorbed by the ____ and returned the the blood
arachnoid membrane
CSF is absorbed when the _____. This system ensures that there is enough CSF to function but not too much CSF that could damage the brain
pressure reaches a certain point.
Brain is made up of 4 regions
Brainstem
Cerebellum
Diencephalon
Cerebrum
What region makes up 80% of the brain?
Cerebrum
The cerebrum is made up of 2 hemispheres. Each hemisphere is divided into ____
5 lobes
Centers for circulatory and respiratory control
Sensory and motor functions for head and neck
Medulla oblongata
Facial sensation and expression
Control of chewing, respiration, and sleep
Pons
Superior colliculus for visual attention
Inferior colliculus for auditory attention
Midbrain
The hindbrain is the
Medulla oblongata and the pons
Why can we have a conversation in a crowded place
IThe midbrain has inferior colliculus for auditory attention
Sleep and consciousness
Varied sensory, motor, and involuntary functions
Reticular formation
Muscular coordination and fine motor control
Cerebellum
The ____ connects the rest of the brain to the spinal cord
Brainstem
The three regions of the brainstem
Midbrain
Pons
Medulla oblongata
All communication between brain and spinal cord involves tracts through the _______
Medulla Oblongata
Medulla Oblongata extends______
fom foramen magnum to pons
Three centers of the Medulla Oblongata
Cardiac center
Vasomotor center
Respiratory center
Heart’s rate and strength of contraction
Cardiac center
Blood pressure control by vasodilation and vasoconstriction
Vasomotor center
regulates respiration rate
Respiratory center:
Other nuclei in medulla oblongata involved in
coughing, sneezing, salivating, swallowing, gagging and vomiting
Four pairs of cranial nerves attach to the medulla oblongata
VIII—vestibulocochlear nerve
IX—glossopharyngeal nerve
X—vagus nerve
XII—hypoglossal nerve
Sensory and motor tracts that connect the brain to the spinal cord
Autonomic respiratory centers regulate the rate and depth of breathing
Fourth ventricle in the posterior
Pons
Pons contains the nuclei of cranial nerves
V—trigeminal nerve
VI—abducens nerve
VII—facial nerve
Superior colliculus for visual attention
Inferior colliculus for auditory attention
Midbrain
Midbrain contains the nuclei of cranial nerves
III—oculomotor nerve
IV—trochlear
Web of gray matter that runs through all levels of brainstem
The Reticular Formation
Functions of the Reticular Formation
Somatic motor control
Cardiovascular control
Sleep and consciousness
Purpose of the Cerebellum
Receives proprioceptive input and makes fine scale adjustments
Fine motor skills (fine tunes movements initiated by the cerebrum)
Integrates and recalibrates information from the cerebrum
where your body is in space
Proprioception
Two regions of the cerebullum
gray cortex, internal white matter (arbor vitae)
arbor vitae
Tree of light
The excessive consumption of alcohol can effect ____
cerebellar function
How excessive consumption of alcohol can effect cerebellar function
Loss of proprioreception (fingers to the nose)
Walking “funny”
Loss of posture ex: standing on 1 foot
Part of the Forebrain
Surrounded by the cerebral hemispheres
The Diencephalon
Three divisions that surround the third ventricle of the Diencephalon
Thalamus
Hypothalamus
Epithalamus
The in-between brain:
Epithalamus (on/around the thalamus)
Thalamus
Hypothalamus (beneath the thalamus)
Gateway to cerebral cortex
Thalamus
Paired oval structures just lateral to the midline (around the third ventricle)
Acts as a filter for somatosensory information
Thalamus
How does the thalamus act as a filter for somatosensory information
Directs sensory info to the correct cerebrum location
Also sends information about where the sensation is coming from
All information coming from the body to the brain goes first through the ______
thalamus (except olfaction)
Thalamus may____ information heading to the cerebral cortex
edit, amplify or diminish
Master control over autonomic nervous system
Master control of endocrine system (hormones)
Hypothalamus
Nuclei in the hypothalamus control:
Regulation of body temperature
Control of emotional behavior (pleasure, aggression, fear, rage, contentment, sex drive)
Control of food intake (nutrient levels, drives hunger)
Control of water intake (salt levels, control urine and thirst)
Forms part of the walls and floor of the third ventricle
Major control center of the autonomic nervous system and endocrine system
The Hypothalamus
In the Hypothalamus____projects inferiorly
Pituitary gland projects inferiorly
Thin roof over the third ventricle
Epithalamus
Endocrine gland that controls day/night regulation using hormone melatonin
Pineal gland
In epithalmus the ___ are involved in developing fear or aversion
nuclei
The two Cerebral Hemispheres Physically separate from each other except where joined by _____
Tracts
Largest of the tracts is _____
corpus callosum
The hemispheres are mostly mirror images, except some language function, localized primarily to the______
left hemisphere
Each hemisphere receives input from and controls the opposite side of the body (_____)
contralaterally
Memory and consciousness can or cannot be located to a specific region
cannot
Type of cerebral tissue that has cell bodies, dendrites, and unmyelinated axons
Gray matter
Type of cerebral tissue that has myelinated axons
White matter
white matter is deep to the gray matter. Gray matter is called ___ (outer portion)
Cortex
There are deep clusters of gray matter called ______(ganglia, but in CNS)
basal nuclei
Lobes of each cerebral hemisphere
Frontal Parietal Temporal Occipital Insula
Lobe of the cerebrum
From frontal bone to central sulcus
Cognition, speech, and motor control
Frontal lobe
Lobe of the cerebrum
From central sulcus to parieto-occipital sulcus
Interprets signals of general senses and taste
Parietal lobe
Lobe of the cerebrum
From parieto-occipital sulcus to occipital bone
Principal visual center
Occipital lobe
Lobe of the cerebrum
From temporal bone to lateral sulcus
Hearing, smell, learning, and memory
Temporal lobe
Lobe of the cerebrum
Deep to lateral sulcus
Taste, visceral sensation, and language
Insula (new lobe)
The cerebrum is the location of:
thought/consciousness/intellect Reasoning Language Memory Judgment Voluntary motor Visual integration Auditory integration
______is carried out in gray matter of the cerebrum
Neural integration
Cerebral gray matter includes
Cerebral cortex (Includes lobes of the brain)
Limbic system
Basal nuclei
White matter:
Deep or superficial to gray matter
The myelinated axons of neurons travel below the gray matter in the central white matter
They are bundled into ____ that traverse parts of the brain
Deep
tracts
In cerebral white matter ____ tracts:
Travel vertically to carry information between cerebrum and rest of body
Projection
In cerebral white matter ____ tracts
Commissures cross between two hemispheres
Corpus callosum is largest
Commissural
In cerebral white matter ____ tracts
Connect regions within same hemisphere
Association
90% of the cerebral cortex is the ___(“recently” evolved)
Neocortex
When we talk about the lobes to the brainfunctionally, we are generally talking about the _____
Neocortex
The “emotional brain”
A collection of deep brain structures that regulate emotions, memories and emotional responses to sensory stimuli
Limbic System
Fear center. Processes fear and coordinates appropriate nervous system response. Recognizes menacing facial expression.
Amygdala
forms, consolidates and retrieves memories
Hippocampus
Limbic system connects to the reticular formation to ____ (i.e. tense muscles, high blood pressure, rapid heart beat, nausea)
coordinate physical responses to fear, emotion and memory
In the limbic system_____functions in spatial memories
Hippocampus
In the limbic system the ____ and ___function together to make calculated decisions based on past experiences
Hippocampus, amygdala
Deep masses of cerebral gray matter
Involved in motor control
Basal Nuclei
_____displays anatomical specificity for function
Cerebral cortex
Each primary sensory cortex
Has an association area (white matter) that processes sensory information
______is first cortical region to receive input for that sense (i.e. visual, auditory, gustatory, sematosensory)
Primary sensory cortex
_____signals motor commands
Primary sensory cortex
Integrates and processes information
Any cortical area that is not primary
Interpretation of sensations, thought, memory, and motor planning
Association cortex
Integrative Brain Functions
Primary cortex, Association cortex
The Cerebral Cortex—Information Processing
Sensory information received by primary sensory cortex
Information relayed to sensory association area
Motor plan enacted and relayed via motor neurons
Cerebral Lobes and Functions: Olfactory and auditory information
Temporal
Cerebral Lobes and Functions:
Primary visual cortex-receives visual input
Other functions-interprets visual input and associated memories
Occipital
Cerebral Lobes and Functions:
Taste
Broca’s and Wernicke’s areas: generation of words, recognition and understanding of spoken words
Insula
(postcentral gyrus) receive sensory input (touch, pressure, pain, temperature)
Primary somatosensory cortex
interprets sensory info, language, combining visual, auditory and sensory info, verbal expression
Other functions of the parietal lobe
a body map. Size of homunculus represents amount of cortical tissue devoted to that region (not the size of the region itself)
The Primary Somatosensory Cortex-(Postcentral Gyrus)Exhibits somatotopy
_____contains primary somatosensory cortex
Postcentral gyrus
______plans and coordinates skeletal muscle movement
Premotor cortex
_____precentral gyrus) skeletal muscle activity
Primary motor cortex
_____Left hemisphere only! Coordinates motor activity for speech
Broca’s Area
______personality, cognition, decision making, planning, recall of object names
Other functions of the Cortical regions of the Frontal Lobe
______ is primary motor cortex
Contains upper motor neurons that control contralateral muscles. Somatotopic
The Primary Motor Cortex (Precentral Gyrus)
Language
Wernicke area, Broca area
Posterior to lateral sulcus of left brain
Recognition of written and spoken language
Wernicke area
Inferior prefrontal cortex of left brain
Speech formation
Broca area
Emotion
Several areas involved
Amygdala outputs to hypothalamus and prefrontal cortex
Acquire and use knowledge
Association areas of cortex
Least understood, most complex
Cognition
Memory
Limbic areas involved
Amygdala creates emotional memories
Hippocampus consolidates long-term memories
Hemisphere specificity for language, analytical reasoning, details
Left
Hemisphere specificity for visual-spatial patterning, intuition, emotion, artistic and musical skills
big picture, holistic integration
Right
Communication and integration is possible through (biggest commissural tract)
corpus callosum
Olfactory (I)
Sensory for Smell
Location: cribiform plate of ethmoid bone
Optic (II)
Sensory for Sight
Location: big X on underside of cerebrum, from retina to thalamus
Oculomotor (III)
Motor for Eye Movement
Location: midbrain to muscles deep to eyeball
Trochlear (IV)
Motor for Eye Movement
Location: lateral midbrain (very small and hard to find)
Trigeminal (V)
BOTH: Sensory in the face; Motor for Muscles that Masticate (chew)
Location: originates in pons, branches throughout face
Abducens (VI)
Motor for eye Movement
Location: originates in pons, to eyeball
Facial (VII)
BOTH: Sensory for taste; Motor for muscles of the face; Motor for making tears and saliva
Location: Originates in pons, branches throughout face
Vestibuloccochlear (VIII)
Sensory for sound and balance
Location: originates in medulla to ear
Glossopharyngeal (IX)
BOTH: Sensory for taste and blood pressure; Motor for swallowing
Location: originates in medulla to tongue and carotid sinus (carotid artery)
Vagus (X)
Vagus to the viscera; BOTH sensory for visceral sensation and motor to smooth and cardiac muscle
Location: Originates in medulla oblongata to visceral organs in the thorax
Accessory (XI)
Mostly motor to muscles of neck and back, swallowing and moving head
Location: originates in medulla goes to sternocleidomastoid and trapezius muscles
Hypoglossal (XII)
Motor to move the tongue
Location: medulla to tongue