Cerebrum
- Largest area of the brain
- characterized by gyri + sulci ( the more smooth=lower IQ)
- allows for processing + motor functions
Cerebellum
- More compact
- contains 50% of neurons, yet one of the smallest parts of the brain(dense)
3 Major portions of brain
- cerebrum
- cerebellum
- brainstem
Longitudinal fissure
Cut of the brain. Left and right
Gyri
Mountains
More surface area
Sulci
Valleys.
More surface area
The more the more intelligence
Corpus callosum
Thick bundle of white matter, lateralization. Thicker corp, better you can do it
Grey matter
The seat of neuron cell bodies, dendrites, and synapses.
- unmyelinated so slower and continuous
White matter
Bundle of axons
- deeper and centralized in brain
- higher adipose content
- most of volume in cerebrum
Brainstem
Most central region, allows for transport of material. Homeostatic(breathing,❤rate,sleep wake, thermo reg) and visceral(emotion) responses occur in brainstem.
Blood is a source of..
Antibodies and macrophages (immunities), bacterial toxins, and other harmful agents
Brain barrier system
Formed by astrocytes
-strictly regulates what substances can get from the bloodstream into the tissue fluid of the brain
Blood barrier system is highly permeable to..
Good -O2 -sugar -CO2 Bad -drugs, alcohol, caffeine, anestetics, cigs
Blood barrier system is slightly permeable to..
- Na
- K
- Ca
*too much salt cells trigger depolarization!!
How much of the bodies ATP does the brain use?
20%
Frontal lobe
Processing. Conscious, voluntary motor control. Ability to plan, memory, aggression,social awareness and judgement
Parietal lobe
General sensory. Taste
Visions fine tuning (texture/additional processing)
Occipital lobe
Primary vision/light center
Temporal lobe
- Hearing,learning,
- smell, memory, emotion, some vision aspects
Insula
Hidden inside. Language center
Grants ability to understand spoken language.
Why don’t we want antibodies +macrophages past the blood brain barrier ?
Autoimmunity-self cells are being attacked by own immune system. Don’t want to attack own body
Extra cells, heat, pain in your brain ( inflammation)
dont want inflation in the brain
The diencephalon
Region above the midbrain/stem between the hemispheres of the cerebrum
Three major derivatives of the diencephalon.. ( major control centers)
- thalamus
- hypothalamus
- epithalamus
Thalamus
-plays a key role in motor signals by relaying signals from cerebellum to cerebrum
-in center of brain
-works with other parts of brain. Make sure signals go to correct lobe
(Sorting hat in Harry potter)
Hypothalamus
- Major control center of autonomic and endocrine systems
- producing hormones
- works with pituitary gland to control hormones
- regulate homeostatic process such as temp(thermo reg), ❤rate/bp, blood glucose levels
Epithalamus
- plays a big role in children
- characterized by pineal gland
- controls sleep and wake rythm
- controls onset of puberty. Maturation is highly dependent of the epithalamus
Basalnuclei
Emotional response.
( most noticeable bump of the thalamus
Pons
- plays key role in relaying signals from cerebellum to cerebrum. Nuclei concerned
- sleep
- respiration rate
- posture
Brainstems two major structures
Pons and medulla oblongata
Medulla oblongata
Receives and integrates signals from spinal cord. Contains
- cardiac center(❤rate)
- vasomotor center(dilation of blood vessels)
- respiratory center(primary resp rate)
- reflex centers(sneezing,coughing,choking)
Reticular formation
- brainstem to all regions of cerebrum, continuously shifting
- loosely organized web of grey matter that runs through brainstem to cortex
Control networks of reticular formation
- somatic motor control
- cardiovascular control
- pain modulation
- sleep and consciousness
- habituation
Somatic motor control
Every muscle contracting at same time to move the signal
Cardiovascular control
Make sure medulla sends correct signal
Pain modulation
Determines where the pain comes from
Sleep and consciousness
PRIMARY ROLE, if any amt of these neurons are damaged you go into acoma
Habituation
Ability to block out signals.
Ex. Have to go to bathroom then get distracted and forget
The cerebellum
- 2nd largest part of brain
- right and left hem connected by vermis
- contains 50% of neurons. Jam packed!
- majority is grey matter
- 10% is white matter( arbor vitae=fast)
Cerebellar peduncles
3 pairs of stalks that connect the cerebellum to the brainstem
-consist of thick bundles of nerve fibers that carry signals to and from cerebellum
Cerebellum functions
-monitors muscle contractions and aids in coordination (regulated)
-evaluation of sensory input➡ compare textures(rough vs smooth,3D ability)
-timekeeping center➡judge timing
-hearing➡primary hearing=temporal. Ability to interpret what we hear
-planning and scheduling tasks, judging time
-
Lesions may result in…
Emotional over reactions and trouble with impulse control.
-works tightly with basal nuclei (governed in thalamus) ex. Impulse control at cerebellum
Sleep occurs in cycles called…( events that reoccur about every 24 hrs)
Circadian rhythms , highest lows in day
Sleep
Temporary state of unconsciousness from which one can awaken when stimulates
While sleeping…
Higher brain function ( need more than one area of brain)
- process in cerebrum
- using whole braun
Restorative effect
ATP stores so we have energy for next day (surplus)
We make our memories here
Serotonin
A wake hormone, higher when wake up
Melanonin
Sleep hormone. Increases 12-24 hrs after wake up
Each sleep cycle is about..
20 min each and sequential
Drowsy..
Metabolic rate still same
Light sleep…
Metabolic, resp, ❤rate decreases
Moderate sleep
Harder to wake , metabolic rates dropping ,
- twitches or “jump” while sleeping stars. Calcium flux in mhacles
Deepest sleep
Metabolic ,❤,resp at lowest. Building of ATP
REM sleep
Rapid eye movement, using ATP breaking up memories, splitting them up and store them somewhere else. Go back to stage one sleep. Brain consumes more O2 then when awake
- longer and most vivid dreams occur here
Language
Process in grey matter
-most occurs in insula=understanding a spoken language
Includes the abil to read, write, speak, and understanding the words assigned to dif regions of he cerebral cortex
Wernicke area
Recognition of spoken and written language. Learned grammar and compositjon
Broca area
How do we talk-motor control associations with speech movement of tongue and mouth
Affective language area
Lesions on insula affect area of Lang. Abil to express time of voice and emotion. Very large part of inaula
Aprosody
Inability to mogulateour tone ( only one tone in voice)
Brain must communicate with rest of body by
Cranial nerves
Most of the input and output travels by way of the
Spinal cord
12 paired of cranial nerves arise from
The base of the brain
Cranial nerves lead to muscles and sense organs located mainly in the…
Head and beck
Most motor fibers of the cranial nerves begin..
In the nuclei of brainstem and lead to glands and muscles
Sensory fibers begin..
In receptors located mainly in head and neck and lead mainly to the brainstem
Most cranial nerves carry..
Fibers between brainstem and ipsilateral receptors and wffectors
Some cranial nerves are classified as..
Motor,sensory, mixed
Sensory cranial nerves
I, II, VIII
Motor cranial nerves…
(III,IV,VI,XI,XII)
Stimulate muscle but also contain fibers of proprioception
Mixed cranial nerves
(V,VII,IX,X)
Sensory functions may be quite unrelated to their motor function
Olfactory nerve I
Sensory nerve
Function=smell
Optic nerve II
Sensory nerve
Function=vision
Oculomotor nerve III
Motor nerve
Function=eye movemtn
The trochlear nerve IV
Motor nerve
Function=eye movement, we can roll our eyes, lateral rotatikn
The trigeminal nerve V
Largest cranial nerve
Mixed( sensory+motor)
Function=feeling in face
Abducens nerve VI
Motor nerve
Function=stimulates eyes laterally ( so eyes don’t cross
Facial nerve (VII)
Mixed (sensory+motor)
Function=
Motor-all of facial expressions
Sensory-taste glands sweet/salty
Vestibulocochlear nerve VIII
Sensory nerve
Function= balance vestibule
Hearing cochlear
Glosskpharyngeal nerve IX
Mixed (sensory+motor) Function= Motor-pharynx (swallowing/deglutination) (Swallowing+gagging,salivation) Sensory-bitter/sour taste
Vagus nerve X
Mixed(sensory+motor)
Function=
Motor-rate for our visceral organs
Accessory nerve
Motor nerve
Function=head+neck
Hypoglossal nerve XII
Motor nerve
Function= speech and digestion to chew. Mostly in tongue