A&P 4.2 (part 1: brain anatomy)

how many meninges are there?

3

double layered external covering

subdivisions:

• Periosteum

• meningeal layer

Faults in word in several areas

dura matter

attached to inner surface of the skull

periosteum

outer covering of the brain

meningeal layer

• middle layer

• web like

Arachnoid layer

• internal layer

• Clings to the surface of the brain

pia mater

• similar to blood plasma composition

• Formed by the ependymal cells in the choroid plexus

• Forms a watery cushion to protect the brain

• Circulated in arachnoid space, ventricles, and central canal of the spinal cord

cerebrospinal fluid or CSF

cerebrospinal fluid accumulates an excerpts pressure on the brain if not allowed to drain

Hydrocephalus

include includes the least permeable capillaries of the body

Blood brain barrier

excludes many potential harmful substances

Blood brain barrier

useless as a barrier against some substances

Blood brain barrier

The blood brain barrier is useless as a barrier against substances, such as

1. Fat and soluble molecules (anesthesia, alcohol, nicotine opiates/opioid, cocaine, methamphetamine, THC, etc.)

2. respiratory gases

3. glucose (across the blood brain barrier (BBB) into the brain, mediated by the facilitative glucose transporter GLUT-1)

Connect the two hemispheres of the cerebrum

Corpus callosum

The right side of the brain controls, the blank side of the body, and the left side of the brain controls the blank side of the body

Left

Right

1. gyri (ridge)

2. sulci (groove)

3. fissure (deep groove)

what are the four parts of the brain stem?

1. Mid brain

2. pons

3. medulla oblongata

4. Reticular formation

• Mostly composed of tracks of nerve fibers

• Has two bulging fiber tracks known as blank

• Has four rounded protrusions known as blank which are the reflex centers for vision and hearing

mid brain

Cerebral Peduncles

corpora quadrigemina

• The bulging center part of the brain stem

• Mostly composed of fiber tracks

• Includes nuclei involving the control of breathing

pons

• The lowest part of the brain stem

• Merges into the spinal cord

• Includes important fiber tracks

• Contains important control centers, such as heart rate control, blood pressure, regulation, breathing, swallowing, and vomiting

medulla oblongata

• diffuse mass of gray matter along the brain stem

• Involved in motor control of the visceral organs

• Reticular activating system or RAS plays a role in a week/sleep cycles and consciousness

reticular formation

• Widespread connections

• Arousal of the brain as a whole

• Reticular activating system or RAS that maintains consciousness and alertness, and functions in sleep and arousal from sleep

recticular formation