Week 13 Human Anatomy - Full Study Guide

Flashcards based on lecture notes to help review and prepare for an exam.

How will the resting membrane potential change?

Becomes more positive (depolarizes) when Na+ enters or K+ is retained, and more negative (hyperpolarizes) when K+ leaves, Na+ entry is reduced, or Cl- enters.

Effect of increased intracellular potassium concentration on membrane potential

More positive (depolarization).

Effect of increased number of open chloride channels on membrane potential

Hyperpolarization.

Effect of increased extracellular sodium concentration on membrane potential

Depolarization.

Effect of decreased number of sodium leaky channels on membrane potential

Hyperpolarization.

Effect of opening voltage-gated potassium channels on membrane potential

Repolarization/hyperpolarization.

Effect of opening voltage-gated sodium channels on membrane potential

Depolarization.

Place neuron structures in order (input → output)

Dendrite → Cell body (soma) → Axon hillock → Axon → Synaptic knob (terminal)

Three differences between graded and action potentials

Amplitude: graded varies, action is all-or-none. Distance: graded decay over short distances, action propagate without decrement. Summation: graded can summate (temporal/spatial); action potentials cannot.

Absolute Refractory Period

No second AP possible (Na+ channels inactivated).

Relative Refractory Period

Second AP possible only with stronger stimulus (K+ efflux still high).

Excitatory neurotransmitters

Depolarize by opening Na+/Ca2+ channels and generating EPSPs.

Inhibitory neurotransmitters

Hyperpolarize by opening K+ or Cl- channels and generating IPSPs.

Event at #1 on AP diagram (Threshold)

V-gated Na+ channels open.

Event at #4 on AP diagram (Peak)

Na+ channels inactivate; V-gated K+ channels fully open.

Event at #5 on AP diagram (Hyperpolarization)

K+ channels closing; membrane temporarily more negative than RMP.

Five core functions of the nervous system

Sensory input, integration/processing, motor output, regulation of homeostasis, higher mental (cognitive, emotion, memory).

Define summation

The additive effect of multiple graded potentials-temporal (same synapse, rapid-fire) or spatial (different synapses simultaneously) to reach threshold.

White-matter structures

Corpus callosum, internal capsule, and septum pellucidum are all composed of myelinated axon tracts (white matter).

Primary visual cortical area

Occipital lobe

Primary auditory cortical area

Superior temporal gyrus

Primary gustatory cortical area

Insula/frontoparietal operculum

Primary somatosensory cortical area

Post-central gyrus

Function of Cranial Nerve I (Olfactory)

Smell

Function of Cranial Nerve II (Optic)

Vision

Function of Cranial Nerve III (Oculomotor)

Most eye mvmt, pupil constrict

Function of Cranial Nerve IV (Trochlear)

Superior oblique eye mvmt

Function of Cranial Nerve V (Trigeminal)

Facial sensation, chewing

Function of Cranial Nerve VI (Abducens)

Lateral rectus eye mvmt

Function of Cranial Nerve VII (Facial)

Facial expression, taste ant 2/3

Function of Cranial Nerve VIII (Vestibulocochlear)

Hearing, balance

Function of Cranial Nerve IX (Glossopharyngeal)

Taste post 1/3, swallowing, carotid reflexes

Function of Cranial Nerve X (Vagus)

Autonomic viscera, voice, swallow

Function of Cranial Nerve XI (Accessory)

SCM/trapezius mvmt

Function of Cranial Nerve XII (Hypoglossal)

Tongue mvmt

How the cerebellum coordinates skeletal muscle movement

Receives proprioceptive feedback → compares intended vs actual movement → sends corrective signals to motor cortex & brainstem nuclei → smooth, coordinated, 'error-corrected' motion.

Motor areas of the cerebrum

Primary motor cortex (pre-central gyrus), premotor cortex, supplementary motor area, frontal eye field, Broca's (motor speech).

Functions of the medulla oblongata

Cardiac center, vasomotor center, respiratory rhythm, reflexes for coughing, sneezing, swallowing, vomiting.

Brain structure that acts as an information filter

Thalamus (filters ascending sensory input before it reaches cortex).

What you'd see if the corpus callosum is damaged

Split-brain (lack of inter-hemispheric transfer) → difficulty naming objects held in left hand, conflicting hand movements, impaired integration of visual-spatial and language tasks.

Define cognition

All higher mental processes: perception, learning, memory, language, reasoning, planning, judgment, emotion, awareness.

Structures located in the pons

Pontine respiratory center, pontine nuclei (relay to cerebellum), cranial-nerve nuclei V-VIII, ascending/descending tracts, middle cerebellar peduncles.

Three sites where the blood-brain barrier is weak

Choroid plexus, hypothalamus, pineal gland (circumventricular organs; also area postrema/posterior pituitary).

Two symptoms you'd expect with no cerebellum

Ataxia (uncoordinated gait) and intention tremor (overshoot/undershoot of targets).

Properties of a reflex

Rapid, involuntary, predictable, stereotyped response to a specific stimulus; requires minimal synapses.

Place the five elements of a reflex arc in order

Receptor → Sensory neuron → Integration center (interneuron) → Motor neuron → Effector.

Properties of the stretch (patellar) reflex

Monosynaptic, ipsilateral, contracts same muscle to maintain length.

Properties of the tendon (Golgi) reflex

Polysynaptic, ipsilateral, relaxes muscle to protect tendon.

Properties of the flexor (withdrawal) reflex

Polysynaptic, ipsilateral, flexors contract to pull limb away from pain.

Properties of the crossed-extensor reflex

Polysynaptic, contralateral, extensor support opposite limb during withdrawal.

Upper Motor Neurons (UMN)

Cell bodies in motor cortex/brainstem; initiate voluntary movement; lesions spasticity, hyperreflexia.

Lower Motor Neurons (LMN)

Cell bodies in anterior horn or cranial-nerve nuclei; directly innervate skeletal muscle; lesions flaccid paralysis, hyporeflexia.

Identify spinal-cord/nerve root parts

Dorsal root, dorsal root ganglion, dorsal horn, ventral horn, ventral root, spinal nerve.

Major ascending pathways

Posterior column-medial lemniscus (fine touch, proprioception), spinothalamic (pain, temperature).