exam 4 stuff

Major sensory relay/filter

Thalamus

Homeostasis / visceral control / “thermostat”

Hypothalamus

Biological clock

Suprachiasmatic nucleus

Satiety / suppress food intake

Ventromedial hypothalamic nucleus

Pineal gland secretion

Melatonin

Speech production

Broca

Language comprehension

Wernicke

Primary motor cortex

Precentral gyrus, frontal lobe

Primary somatosensory cortex

Postcentral gyrus, parietal lobe

Coordination/posture/balance

Cerebellum

Piriform

Smell / olfaction

Fear/anger emotional cues

Amygdaloid body

Graded vs. action potentials

Graded: short, variable strength, weaken with distance, can summate. AP: long-distance, all-or-none.

AP initiation

Initial segment / trigger zone.

AP ion movements

Depolarization = Na⁺ IN. Repolarization = K⁺ OUT. After-hyperpolarization = K⁺ channels remain open longer.

Stimulus strength vs. speed

Stronger stimulus → higher firing frequency, not greater AP amplitude. Larger diameter + myelin → faster conduction.

Saltatory conduction

APs regenerate at nodes of Ranvier along myelinated axons.

Chemical synapse

AP arrives → Ca²⁺ IN → vesicle exocytosis → transmitter binds → postsynaptic graded potential.

Ending transmitter effects

Reuptake, enzymatic degradation, diffusion away.

EPSP vs. IPSP

EPSP: depolarizes toward threshold. IPSP: typically hyperpolarizes away; K⁺ OUT or Cl⁻ IN.

Temporal vs. spatial summation

Temporal = one neuron, rapid repeated inputs. Spatial = multiple neurons, different locations.

Neurotransmitters

ACh: skeletal NMJ. NE: most sympathetic postganglionic neurons. GABA: inhibitory brain. Glutamate: excitatory brain.

Receptors

Effect depends on receptor. Direct/fast = ion channel. Indirect = receptor → G protein → adenylate cyclase → cAMP.

Location terminology

Cell bodies: nucleus CNS / ganglion PNS. Axon bundles: tract CNS / nerve PNS.

Astrocytes

Regulate the chemical environment around CNS neurons.

Anterior crossing, most joints

Flexion

Posterior crossing, most joints

Extension

Lateral shoulder crossing

Abduction — away from midline

Medial shoulder crossing

Adduction — toward midline

Parallel versus pennate muscles

Parallel: greater shortening, less force

Bipennate/multipennate muscles

Many short, oblique fibers packed together: greater force, little shortening

First-class lever

Fulcrum in the middle

Standing on toes: second class

Load in the middle; force advantage

Most skeletal muscles: third class

Effort in the middle; speed/range advantage, force disadvantage

Second versus third class

Second = strength; third = speed/range