Skip to main content
Back

Anatomy & Physiology Exam 4 Study Guide

Control buttons has been changed to "navigation" mode.
1/27
  • Characteristics of graded potentials

    Graded potentials vary in magnitude, are localized, and decrease in strength as they spread. They differ from action potentials which are all-or-none and propagate without decrement.

  • Importance of graded potentials to action potentials

    Graded potentials summate to reach threshold, triggering action potentials that propagate signals over long distances.

  • Types of sensory receptors by stimulus

    Sensory receptors are matched to stimuli such as mechanoreceptors (touch), thermoreceptors (temperature), photoreceptors (light), chemoreceptors (chemicals), and nociceptors (pain).

  • Coding of stimulus intensity by action potentials

    Action potentials code stimulus intensity by frequency (more frequent firing for stronger stimuli) and by recruiting more neurons for larger stimuli.

  • Structures of CNS and PNS

    CNS includes the brain and spinal cord; PNS includes all nerves outside the CNS, including spinal and cranial nerves.

  • Information in dorsal vs ventral roots of spinal nerves

    Dorsal roots carry sensory (afferent) information to the CNS; ventral roots carry motor (efferent) information away from the CNS.

  • When do sensory and motor axons mix in spinal nerves?

    Sensory and motor axons mix after the dorsal and ventral roots merge to form the spinal nerve proper.

  • Branching of spinal nerves and limb connection

    Spinal nerves branch into dorsal and ventral rami; the ventral ramus connects with limbs and anterior body wall muscles.

  • Importance of nerve plexuses

    Nerve plexuses allow complex innervation of limb muscles by mixing fibers from multiple spinal nerves, providing redundancy and coordinated control.

  • Actions of muscles innervated by radial and ulnar nerves

    Radial nerve controls wrist and finger extension; ulnar nerve controls finger flexion and intrinsic hand muscles.

  • Actions of muscles innervated by femoral, obturator, and sciatic nerves

    Femoral nerve controls thigh flexion and leg extension; obturator nerve controls thigh adduction; sciatic nerve controls leg flexion and foot movements.

  • Neuromuscular junction and end plate potential

    The neuromuscular junction is the synapse between a motor neuron and muscle fiber; the end plate potential is the depolarization of the muscle membrane that triggers contraction.

  • Efferent nerve synapse with smooth muscle and glands

    Efferent nerves synapse with smooth muscle and glands via varicosities releasing neurotransmitters diffusely rather than at a single junction.

  • Intrinsic vs learned reflexes

    Intrinsic reflexes are innate, automatic responses; learned reflexes are acquired through practice.

  • Can intrinsic reflexes be modified?

    Yes, intrinsic reflexes can be modulated by higher brain centers and experience.

  • Polysynaptic vs monosynaptic reflex arcs

    Monosynaptic reflexes involve one synapse between sensory and motor neurons; polysynaptic reflexes involve one or more interneurons.

  • Extrafusal vs intrafusal muscle fibers

    Extrafusal fibers generate force for muscle contraction; intrafusal fibers are part of muscle spindles that detect stretch.

  • Muscle spindle action potentials and information sent

    Muscle spindles send action potentials to the CNS about muscle length and rate of stretch, aiding proprioception.

  • Muscle stretch reflex and reciprocal inhibition

    The muscle stretch reflex causes contraction of stretched muscle; reciprocal inhibition relaxes antagonist muscles to allow smooth movement.

  • Primary vesicles of the brain

    The three primary brain vesicles are prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain).

  • Secondary vesicles from primary vesicles

    Prosencephalon divides into telencephalon and diencephalon; mesencephalon remains undivided; rhombencephalon divides into metencephalon and myelencephalon.

  • Brain structures from secondary vesicles

    Cerebral hemispheres develop from telencephalon; thalamus from diencephalon; midbrain from mesencephalon; cerebellum from metencephalon; medulla oblongata from myelencephalon.

  • Structure of the diencephalon

    The diencephalon's walls are formed by the thalamus, the floor by the hypothalamus, the roof by the epithalamus, and the center contains the third ventricle.

  • Cerebrospinal fluid (CSF) functions and location

    CSF cushions the brain, removes waste, and provides nutrients. It is found in ventricles and subarachnoid space and secreted by the choroid plexus.

  • Meninges of the brain and relation to CSF

    The meninges are dura mater, arachnoid mater, and pia mater. The arachnoid mater encloses the subarachnoid space where CSF circulates.

  • Major functions of medulla oblongata, cerebellum, hypothalamus

    Medulla controls autonomic functions; cerebellum coordinates movement and balance; hypothalamus regulates homeostasis and endocrine functions.

  • Functions of precentral and postcentral gyri

    Precentral gyrus is the primary motor cortex; postcentral gyrus is the primary somatosensory cortex.