Anatomy - BRAIN (part uno)

4 main parts of the brain

Brain stem/diencephalon/cerebellum/cerebrum

White matter

Tracts (fibers = axons = connections between neurons)

Gray Matter

Dendrites/somas/synapses

What is Selective Serotonin Reuptake Inhibitors

Antidepressants

What does SSRIs do?

Block serotonin from leaving → higher serotonin

How many synapses in brain?

1,000 trillion synapses. More than number of stars in galaxy!

How many total neurons?

86 billion neurons

What are neuroglia

Support/protect neurons

CNS

Tracts

How much neuroglia is there?

10-50 trillion (3-3.5 lbs)

1 brain region may be involved in several functions at same time!

TRUE

One function (Moving arm) can involve several brain regions

TRUE

What is the average amount of synapses in neuron?

1,000

How much does brain weigh?

3.2-3.5 lbs

Brain stem parts

Midbrain/Pons/Medulla oblongata

Parts of Diencephalon

Hypothalamus/Thalamus/Epithalamus

Parts of Cerebrum

Cortex/Limbic system/basal nuclei

How many times more surface area in brain to fit more neurons?

3 times more!

PNS connects to

Nerves

Spinal cord and brain protected by

Meninges! (membranes)

Nerves and tracts are both

Axon bundles

There is no space between arachnoid and Pia Mater

FALSE

There is no space between DURA mater and Arachnoid

TRUE

Brain floats in

Cerebral Spinal Fluid

What is space between Arachnoid + Pia Mater called

Subarachnoid Space

What is Cerebral Spinal Fluid made of

From blood/ependymal cells in ventricles (cavities) in brain

CSF’s function

Buoyancy (1500g/5g) Protects/regulates chemical environment/ waste removal

WHERE is CSF made

Lateral ventricles → foramen of monro → 3rd ventricle → 4th ventricle → leaves out through apertures → subarachnoid space/circulates around brain

Where does old CSF return to?

Bloodstream → heart

Hydrocephaly happens…

during development

Hydrocephaly process

Excessive CSF → brain ventricles dilate → too much skull pressure. No circulation

Blood Brain Barrier

Protect brain’s neurons from potential toxins/unwanted substances in blood

Brain is what percent of body weight

2%

Brain consumes __% of oxygen/glucose

20%

Cut off blood flow to brain for 10 seconds?

You pass out

Cut off blood flow to brain for 1-2 mins?

Neurons don’t function correctly

Cut off blood flow to brain for 4 mins?

Permanent brain damage

Capillaries

Tiniest blood vessels/thin walls/feed oxygen and nutrients to tissues

What do typical capillaries do?

Lets water/small solutes move from blood → ISF (Interstitial Fluid)

Astrocytes limit solutes that leak out of capillaries by

wrapping around capillaries

What can cross Blood Brain Barrier

Lipophilic substances (alcohol/nicotine/caffeine/O2/CO2/glucose/Na and K)

Glucose crosses the Blood Brain Barrier

easily!

Na and K crosses Blood Brain Barrier

through Ion Channels

Chemotherapy drugs can’t cross…

Blood Brain Barrier

Example of why crossing BBB isn’t good thing

Brain tumors treated w/radiation (too much damages healthy cells)

basal nuclei

repetitive behaviors/intentional movement

If amygdala is stimulated…

feel extreme angry/violence/fear

What lobe is Broca’s area located in?

Frontal lobe

What is the parallel area OPPOSITE Broca’s?

Affective Langauge Area: speech emotion/tone

What is cortex opposite Wernicke’s area?

Recognize speech emotion in others!

What is Wernicke’s Area between in?

Parietal/occipital lobe

Association =

Interpretation