bio 225 neurobiology

brain

the integrating center

spinal cord

mediates information flow between the brain and the body

nuclei

groups of neuronal cell bodies within the CNS

tracts

bundles of many axons within the CNS

nerves

bundles of many axons outside the CNS

ganglia

groups of neuronal cell bodies outside of the CNS 

white matter

has a shiny, bright appearance

primarily composed of myelinated axons

grey matter

has a dulled appearance

contains dendrites, cell bodies, & unmyelinated axons

ipsilateral

same side

contralateral

opposite side

ascending tracts

carry afferent/sensory signals within the CNS

descending tracts

carry efferent/motor signals within the CNS

medulla oblongata

regulates breathing, HR, and blood pressure

pons

communicates between medulla, cerebellum, and forebrain

cerebellum

coordinates motor behaviors

the hindbrain

directly connects to the spinal cord

the forebrain

controls higher level processes

corpus callosum

a white matter tract that connects the left and right cerebral hemispheres

cerebral cortex

the surface gray matter which can be divided into functional areas

primary motor cortex

• controls discrete skeletal muscles

• stimulation results in specific movements on opposite side of the body

damage to the primary motor cortex

leads to paralysis of voluntary movements that are rarely regained while reflexes remain intact

premotor cortex

coordinates movements of groups of muscles

damage to the premotor cortex

leads to loss of skill that can often be relearned

primary somatosensory cortex

primary input from touch, temperature, and pain receptors in skin and muscle on opposite side of body

damage to the primary somatosensory cortex

leads to loss of sensation that rarely returns

somatosensory association area

interpretation of sensation and integration with memory

damage to the somatosensory association area

leads to a loss of identification that can be relearned

primary visual cortex

primary input from optic tracts, activated by visual stimuli 

visual association areas

integration and perception

thalamus

relay station, filters and sorts sensory inputs, routes information

hypothalamus

homeostasis, regulates pituitary gland

thalamus + hypothalamus

the limbic system

hypothalamus role in homeostatic regulation

• stress response; regulates food intake, body temperature, and circadian rhythm; helps maintain ion and water balance

sympathetic nervous system

fight or flight, most active during stress or physical activity increases heart rate and breathing, directs blood to working muscles

parasympathetic nervous system

resting and digestion, most active during periods of rest, redirects energy toward maintenance activities

sympathetic preganglionic neuron

short axon, releases acetylcholine

parasympathetic preganglionic neuron

long axon, releases acetylcholine

sympathetic postganglionic neuron

express nicotinic AChRs, long axon, releases norepinephrine

parasympathetic postganglionic neuron

express nicotinic AChRs, short axon, releases acetylcholine

sympathetic target organs

express adrenergic receptors

parasympathetic target organs

express muscarinic AChR

acetylcholine

first nt discovered, synthesized at axon terminals of cholinergic neurons, nt at neuromuscular junction and parts of central and peripheral nervous systems

acetylcholine receptors

nicotinic and muscarinic

nicotinic AChR

ionotropic, excitatory, found in autonomic and motor neurons, non specific cation channel

muscarinic AChR

metabotropic, excitatory or inhibitory, found in smooth and cardiac muscle, glands and CNS

norepinephrine/noradrenaline

catecholamine, functions mostly as a sympathetic nt

adrenergic receptors

metabotropic, respond to epinephrine from the adrenal gland, found throughout the body, diverse effects based on receptor subtype

olfactory bulb

sense of smell

amygdala

emotions, fear, aggression

hippocampus

learning and memory