Midterm 1 - Neuroanatomy, Blood Supply, MCDB, CNS, PNS, CNs Flashcards
Sectioning the Brain
(Image)
Directions and the Brain
Top of Brain - Dorsal (also the back)
Bottom of Brain - Ventral (also the belly)
Front - Rostral (anterior)
Back - Caudal (posterior)
Lateral - Towards side
Medial - Towards middle
Planes of the Brain
(Image)
Lobes of the Brain
(Image)
Sulcus vs. Fissure vs. Gyrus
Brain is gyrencephalic.
Sulcus
- Groove
Fissure
- Deep groove
Gyrus
- Bump
Ventricles
(Image)
- Lateral (2)
- 3rd
- 4th
- Cerebral Acqueduct
Corpus Callosum
- Thick bundle of axons that facilitates the transmission of information from one hemisphere to the other.
- Connects like areas of brain.
CSF
- Fills ventricles
- Made by choroid plexus of each ventricle. The CP of each ventricle gets a blood supply and takes what it wants to make CSF (clear part of blood).
- Drains to 4th ventricle where it becomes a part of the blood supply again.
Meninges in the CNS
- Protective sheaths around brain and spinal cord.
- Pia Mater - thin, delicate layer on top of brain
- Arachnoid Layer - Hollow space where the blood vessels supply the brain with blood
- Dura Mater (outermost) - Beneath skull; thick, tough
Meninges in the PNS
No arachnoid layer, just dura and pia.
What does blood carry to the brain?
- Glucose
- Oxygen
Brain is only 2% of body’s weight but uses 20% of body’s oxygen and 20% of body’s glucose.
7 min w/o oxygen and neurons begin to die.
Arteries Going to Brain
- Carotid (2) - come off front of heart, go up front of spinal cord, go to front of brain
- Vertebral (2) - come off heart and go up spinal cord, supplying blood to the back 1/2 of the brain (go thru hole in bottom of skull: “foramen magnum”).
Primary Vein Leaving Brain
Jugular (carries de-oxygenated blood away)
2 Ways Blood Supply to Brain Is Interrupted
- Stroke/CVA - Plaque in large artery breaks free and gets stuck in smaller branch (in brain).
- Anneurism - Outpouching of artery. Bursts and blood doesn’t get to the neurons it needs to get to.
Blood-Brain Barrier
Comprised of tight junctions of epithelial cells that make up the walls of arteries in the brain. Actually the lining of the arteries themselves.
MCDB
Molecular Cellular Developmental Biology
- We start as a tube and develop from the inside out, forming 6 layers that become the brain.
- Proliferation of neural stem cells in SVZ
- Migrate to radial glia cells
- Differentiate as climb up radial glia
Encephalons
Tel, Di, Mes, Met, Myel: Become brain and spinal cord
- Telencephalon - Forebrain; Lateral ventricles, cerebral cortex (F-POT), Basal Ganglia, Limbic; front part of brain; becomes brain proper
- Diencephalon - Forebrain; 3rd ventricle, thalamus, hypothalamus
- Mesecephalon - Midbrain, cerebral aqueduct, tectum, tegmentum
- Metencephalon = Hindbrain; 4th ventricle; cerebellum, pons
- Myelencephalon = Hindbrain, medulla
Embryonic Brain Development
(Encephalons)
Encephalons
(Image of Brain)
Brainstem
- Medulla (myelencephalon)
- Pons (metencephalon)
- Midbrain (mesencephalon)
CNS
- Brain + Spinal Cord
- Encased in bone
PNS
- Cranial nerves (except for Optic II which is part of diencephalon tract)
- Spinal Nerves
- All nerves that come from your entire body
Somatic - Receives sensory info and controls movement of skeletal muscles
ANS
- Sympathetic
- Parasympathetic
Cranial Nerves
(Overview Image)
Cranial Nerves
(All 12)
O, O, O, Titty, Twat, Ass, Fuck, A, Girl’s, Vagina, Says, Hi
- Olfactory - Smell
- Optic - Vision
- Oculomotor - Eye movement
- Trochlear - Eye Movement
- Trigeminal - Jaw Movement
- Abducens - Eye Movement
- Facial - Face muscles
- Auditory - Hearing
- Glossopharyngeal - Muscles of throat and larynx
- Vagus - Internal Organs
- Spinal Accessory - Neck Muscles
- Hypoglossal
Cranial Nerve
Nerve that emerges directly from brain.
Don’t go into spinal cord or thalamus.
Brain
Cortex + Brain Stem
Brain:
Gray Matter
v.
White Matter
Gray
- Cell Bodies (outside)
White
- Myelin (inside)
Spinal Cord:
Gray Matter
v.
White Matter
White
- Myelin (outside)
Gray
- Cell bodies (inside)
Opposite of brain
Afferent Axon
An axon directed toward the CNS, conveying sensory information
***Dorsal Root***
Efferent Axon
An axon directed away from the CNS, conveying motor commands to muscles and glands
***Ventral Root***
Law of Bell & Magendie
Segregation of Spinal Cord
- Anything above the midline (dorsal portion of spinal cord) is info going to brain from the senses.
- Anything below the midline (ventral portion of spinal cord) is info coming from the brain to the muscles.
2 Types of Cells in CNS
- Neurons
- Glia
Types of Glia Cells
- Oligodendrocytes
- Schwan Cells
- Microglia
- Macroglia
- Astrocyte
Oligodendrocyte
- CNS
- Big
- Provide myelin
Schwan Cell
- PNS
- Smaller than oligo
- Provide myelin
Substantia Gelatinosa
- Junction of oligos & schwan
- Entry to CNS (bacteria can get in)
- Where PNS goes into spinal cord
Microglia + Macroglia
Both involved in immune system in brain.
Eat things
Astrocytes
- Starts of the nervous system
- Support neural transmission
- Store glucose (takes from arteries)
- Store ions
- Maintain balance of NTs at synpse by sucking up extra NT or supplying NT when there’s not enough
Glia Cells
v.
Neurons
Glia Cells
- Can proliferate out of control and form tumors (“glyomas”)
- Can mutate
Neurons
- Don’t divide
- Once differentiated, stay a particular type of cell
- Never form tumors
Time Frame for Neuron Proliferation, Migration and Differentiation
- Start in 2nd trimester and continues thru 2 yrs old
- Neurons steadily die after age 2 and perhaps reach peak neuronal density before born
Synaptic Plasticity
Brain can change.
A neuron’s ability to form new synapses with other neurons.
How you learn (a physical structure is created every time you learn)
3 Things Affecting Brain Health
- Exercise
- Nutrition
- Sleep
