meow

biology 30 nervous system - parts of brain

gray matter

made up of cell bodies, dendrites, and short unmyelinated axons

white matter

made up of myelinated axons

meninges

the brain and spinal cord are enclosed in three layers of tough elastic tissue": dura mater, arachnoid, and pia mater

dura mater

outer layerar

arachnoid

middle layer

pia mater

inner layer

cerebrospinal fluid (csf)

circulates in the subarachnoid space (space between arachnoid and pia mater). acts as a shock absorber and cushion, circulates hormones, nutrients, white blood cells, across blood brain barrier

blood brain barrier (bbb)

the separation between the blood and the cns. capillaries in the brain have tight junctions - each capillary cel is tightly fused to the one beside it, preventing substances from moving between the cells. most nutrients must be transported through specific protein carriers in order to leave the capillaries and enter the cerebrospinal fluid. lipid soluble molecules are able to diffuse through the cell membrane itself and into the csf

forebrain

largest part of the brain, divided into left and right hemispheres. contains cerebrum and cerebral cortex

cerebral cortex

outer sheet of neurons on surface of cerebrum made up of grey matter that has deep fissures (folds to increase surface area)

the coordinating centre for sensory info and voluntary motor actions. more
“folds” = higher function

occipital lobes

receives and analyzes visual information

temporal lobes

main role : auditory reception

also understands speech, retrieves visual and verbal memories and processes visual information, processes smell

parietal lobes

processes information about spatial awareness, taste

somatosensory cortex

part of the parietal lobes. receives and processes sensory information from the skin

frontal lobes

associated with conscious thought, intelligence, memory, personalityprim

primary motor cortex

located inside the frontal lobe. contains motor areas for precise, voluntary motor movement

homunculus

a representation of what a body would look like if the number of neurons associated with it matched the size of the body part

broca’s area

located in the left hemisphere. impacts speaking ability.

expressive aphasia

damaged broca’s area. patient can understand language, but is unable to speak it

wernick’s area

left hemisphere. associated with language comprehension.

receptive aphasia

damaged wernick’s area. person could speak, but it would not make any sense.

thalamus

major integrating centre of the brain. sorts and directs incoming sensory info to appropriate lobes of the cerebrum

corpus callosum

connects the right and left hemispheres.

hypothalamus

homeostatic regulation of blood pressure, hunger, thirst, sleep, body temperature, water balance. regulates the release of hormones from pituitary glands

apg

develops from a fold in the roof of the mouth. release of hormones controlled by hypothalamus

ppg

develops from a projection of the hypothalamus. release of hormones controlled by hypothalamus

limbic system

associated with learning, reasoning, personality, emotions, and memory. regulates hormone release in response to emotions. reward and punishment center of the brain = learning

hindbrain

consists of the cerebellum, medulla oblongata, and pons

cerebellum

aka “little brain.”

unconscious coordination of posture, reflexes, body movements, as well as fine, voluntary motor skills such as riding a bike

receives sensory information from proprioceptors about the position of joints and lengths of muscles

medulla oblongata

controls autonomic responses such as breathing, heart rate, swallowing, coughing, constriction/dilation of blood vessels and blood pressure.

pons

minor relay centre between right and left halves of brain. conducts signals from the brain to the medulla oblongata/cerebeullum to the brain. plays a role in autonomic functions such as breathing, sleep, wake, etc

midbrain

receives and relays visual and auditory information. plays an important role in eye movement and control of skeletal muscles.

positron-emission tomography

areas of the brain in use have higher energy demands. inject radioactive glucose into a patient and scan during different tests on patient

magnetic resonance imaging (Mri)

a giant magnet induces hydrogen atoms in the brain to emit radio signals

dorsal root

bundle of nerve finbers that emerge from spinal cord. cell bodies of sensory neurons (spinal cord)

ventral root

bundle of nerve finbers that emerge from spinal cord. contains motor neurons