Biology and Behavior

sensory neurons

transmit sensory information from receptors to the spinal cord and brain

motor neurons

transmit motor information from the brain and spinal cord to muscles and glands

interneurons

found between the sensory and motor neurons and are the most numerous. located predominantly in the brain and spinal cord and are associated with reflexes.

reflex arcs

ability of interneurons in the spinal cord to relay information to the source of the stimuli while simultaneously routing it to the brain

central nervous system

brain and spinal cord

peripheral nervous system

most cranial and spinal nerves. divided into somatic (voluntary) and autonomic (automatic)

autonomic system

divided into parasympathetic (rest & digest) and sympathetic (fight/flight) branches

hindbrain

contains the cerebellum, medulla oblongata, and reticular formation

midbrain

contains the inferior and superior colliculi

forebrain

contains the thalamus, hypothalamus, basal ganglia, limbic system, and cerebral cortex

thalamus

relay station for sensory information, everything except smell

hypothalamus

maintains homeostasis and integrates with the endocrine system through the hypophyseal portal system that connects it to the anterior pituitary

basal ganglia

smoothens movements and helps maintain postural stability

limbic system

controls emotions. contains the septal nuclei, amygdala, and hippocampus

septal nuclei

involved in feelings of pleasure, pleasure-seeking behavior, and addiction

amygdala

controls fear and aggression

hippocampus

consolidates memories and communicated with other parts of the limbic system through an extension called the fornix

cerebral cortex

divided into four lobes: frontal, parietal, occipital, and temporal

frontal lobe

controls executive function, impulse control, long-term planning, motor function, and speech production

parietal lobe

controls sensations of touch, pressure, temperature, and pain; spatial processing; orientation; and manipulation

occipital lobe

controls visual processing

temporal lobe

controls sound processing, speech perception, memory, and emotion

left cerebral hemisphere

dominant hemisphere for language. controls the majority of functions on the right side of the body

acetylcholine

used by the somatic nervous system (to move muscles), the parasympathetic nervous system, and the central nervous system (for alertness)

dopamine

maintains smooth movements and steady posture

endorphins and enkephalins

natural pain killers

epinephrine and norepinephrine

maintain wakefulness and alertness, and mediate fight-or-flight responses. epinephrine tends to act as a hormone, and norepinephrine tends to act more classically as a neurotransmitter. both released by the adrenal medulla and cause physiological changes associated with the sympathetic nervous system

GABA and glycine

act as brain "stabilizers"

glutamate

acts as an excitatory neurotransmitter in the brain

serotonin

modulates mood, sleep patterns, eating patterns, and dreaming

cortisol

stress hormone released by the adrenal cortex

testosterone

produced by the testes in males. mediates libido and increases aggression. released by the adrenal cortex

estrogen

released by the adrenal cortex and produced by the ovaries in females. mediate libido

neurulation

nervous system development. notochord stimulated overlying ectoderm to fold over, creating a neural tube topped with neural crest cells

neural tube

becomes the central nervous system

neural crest

cells spread out throughout the body, differentiating into many different tissues

primitive reflexes

exist in infants and should disappear with age. Most serve (or served, in earlier times) a protective role. They can reappear in certain nervous system disorders.

rooting reflex

Infant reflex where a baby will turn its head towards a stroke of cheek and open its mouth

moro reflex

Infant reflex where a baby will extend the arms and slowly retract them and cry on response to a sensation of falling

babinski reflex

Infant reflex where if its foot is stroked, the baby's toes fan out

grasping reflex

the infant grabs anything put into his or her hand

developmental milestones

gross and fine motor abilities progress head to toe and core to periphery. social skills shift from parent-oriented to self-oriented to other-oriented. language skills become increasingly complex