Exam 1 Study Guide

Topographic Organization

Physical features of the brain

Somatotopic Organization

Visual representation of the brain

Frontal Lobe Functions

Executive functions, control of movement, personality, emotions, M1 (primary motor cortex)

Parietal Lobe Functions

Sensory, perception, body image, spatial awareness, S1 (sensory cortex)

Occipital Lobe Functions

vision

Temporal Lobe Functions

Hearing, speech comprehension, memory & aspects of learning

What is Sulci

groove/alley

What is Gyri

bumps/ridges

Major Sulci in Brain

Central Sulcus= divides frontal and parietal lobes

Sylvian/Lateral Fissure= divides frontal/parietal from the temporal lobe

Medial Longitudinal Fissure= divides the right and left hemispheres of the brain

Major Gryi in brain

Precentral gyri= anterior portion of the central sulcus

Postcentral gyri= posterior portion of the central sulcus

Telencephalon

consists of two hemispheres with four lobes

Contains limbic system and basal ganglia

Limbic System controls emotion, learning, motivation, memory

Basal Ganglia initiates and controls movement; cognition and emotion

Diencephalon

Hypothalamus

Maintains homeostasis

Regulation of organ and endocrine functions

Eating, reproduction, motivation behaviors

Sleep rhythm

Thalamus

Relay station for almost all senses except olfactory

Integrates sensation

Processes emotional information

Regulate consciousness, arousal & attention

Brainstem

Connects the spinal cord and cerebrum; integrates information and regulates vital function

Medulla - life support center (BP & HR)

Pons - regulates breathing

Midbrain - visual and auditory reflexes

Cerebellum

Coordination of movement

Controls range and force of movement

Balance

Motor learning/memory

Telencephalon Lesion

cognitive, motor, sensory, emotional impairments

Limbic system Lesion

emotional instability, memory and motivation issues

Soma/cell body functio

integration of info into nucleus

Metabolic center

What are glial cells

provide electrical insulation ; keep cells clean

Type of Glial Cells

Microglial and Macgroglial

Microglial cell functions

Immune system of the CNS

Clean the neural environment -phagocytes

Activated during NS development

Macroglial cell functions

Astrocytes: part of the blood brain barrier; connects neurons and blood capillaries, providing nutrition to neurons

Oligodendrocytes (CNS): forms myelin to insulate axons

Schwann Cells (PNS): form myelin to insulate axons

In broad terms, what are stem cells?

Undifferentiated cells

Self-renewal

Differentiate into most type of neurons and glial cells

Broadly understand what the purpose of CSF

CSF: helps maintain homeostasis; shock absorber; fluid transport system

Neuroplasticity

Ability of neurons to change their function, chemical profile, or structure

Habituation

Learning and memory

Recovery after injury

Neural Tube Formation

Neural Plate

Neural Groove

Neural Tube

Neural Crest

Classification systems of neurons: # of processes

Unipolar

Single projection

No true unipolar neuron

Pseudounipolar

One projection that splits into 2 axons, no true dendrite

Bipolar

1 axon and 1 dendritic root

Multipolar

1 axon and many dendrites

Local Potentials

transmit information over short distances

Action Potentials

transmit information along an axon by repeated generation of a signal

Resting Membrane Potential

Membrane channels are closed, around -70mV

Threshold

When there is a stimulus that reaches the membrane; voltage gated Na+ channels OPEN and Na+ enters which depolarizes.

Depolarization

More voltage-gated Na+ channels open and continue to depolarize the cell. Na+ channels start to close once peak hits +35mV.

Repolarization

Voltage-gated K+ channels open and K+ from inside, exits the cell and takes positive charges OUT of the cell

Hyperpolarization

Voltage-gated K+ channels remain OPEN & K+ continues to leave the cell which restores the polarized membrane potential

Difficult to initiate another AP =

refractory period

- prevents backward propagation of AP

Two refractory periods

Absolute refractory period: membrane unresponsive to stimuli

Relative refractory period: stimulus must be stronger than normal to create AP

Return to RMP

Na+-K+ pump: moves Na+ out of neuron and K+ back into neuron

Saltatory Conduction

Nodes of Ranvier: small unmyelinated patches located on myelinated axons

AP appears to "jump" from node to node

Synaptic Transmission

the process of sending a signal from one neuron to another across a tiny gap called the synapse

AP reaches presynaptic terminal → Ca++ enters presynaptic terminal → vesicles move toward edge → terminal releases neurotransmitter into synaptic cleft → neurotransmitter binds to postsynaptic membrane receptor → membrane channel changes shape

Multiple Sclerosis:

autoimmune disease where there is a demyelination of the CNS

Characteristics of MS

Impaired sensations (numbness)

Motor weakness

Impaired vision

Goes through relapse and remission phases

Prognosis- can get better over time

Treatment- no cure; as OTs, lifestyle changes, energy saving schedules

Guillain Barre Syndrome

autoimmune disease where there is a demyelination of the PNS

Characteristics of GB

Motor weakness, paralysis

Atypical sensations/pain

Motor CNS most affected

Gradual improvement after 2-3 weeks

Treatment- strengthening and regaining functional mobility, energy conservation techniques

Myasthenia Gravis

is an autoimmune disease where there is a decreased number of functional muscle membrane ACh receptors

Characteristics of Myasthenia Gravis

Motor weakness

Sensory is not impacted

High survival rate

OTs work to create adapted tools, energy conservation

Sympathetic NS in the body examples

Dilates pupil

Inhibits salivation

Relaxes bronchi, increases heart rate

Inhibits digestive activity

Stimulates glucose release by liver

Parasympathetic NS in the body examples

Constrics pupil

Stimulates salivation

Constricts bronchi, decreases heart rate

Stimulates digestive activity

Stimulates gallbladder

Bell’s Palsy:

Viral infection

Lesion to the facial nerve

Unilateral paralysis of facial muscles

Salivation and production of tears affected

Rectory within 2 months

Trigmenial Neuralgia

Compression of trigeminal nerve

Severe sharp, stabbing pain in face

Variable prognosis

Musculocutaneous nerve

Elbow flexion

Sensory: lateral forearm

Median Nerve

Wrist & finger flexion, forearm pronation, thumb movement

Sensory: Ventral lateral half of the hand, nail beds of index, dorsal middle and lateral half of the ring finger

Ulnar Nerve

Wrist & finger flexion

Medial half of hand ventrally and dorsally

Radial Nerve

Elbow, wrist, hand extension, and supination

Sensory: lateral half of the dorsal hand

Nerve degeneration

Retrograde: degeneration of the proximal axon

Orthograde: degeneration distal axon

Nerve regeneration

CNS oligodendrocytes don't support regeneration

PNS Schwann cells allow for regeneration

Sprouting: growth of a new branch of damaged axons

Avulsion

Nerve is torn from attachment to spinal cord

Most severe

Rupture

nerve is torn but not at the spinal cord

Neuroma

scar tissue that forms and puts pressure on nerve

Stretch

damaged nerve, not torn

Motor Changes in Nerve Injuries

paralysis, weakness, muscle atrophy

Sensory Changes in Nerve Injuries

loss or decrease sensation, impaired proprioception

Autonomic Changes in Nerve Injuries

dizziness, blurred vision, digestive changes

Trophic Changes in Nerve Injuries

shiny skin, brittle nails

Neuropraxia- Class I

Repeated pressure, stretch, vibration on nerve (typing, fingers/wrist overuse)

Impingement or compression that leads to loss of myelin at axon

Full recovery

Axonotmesis- Class II

Crushing of nerve (after dislocation)

Axon cut but myelin and connective tissue still in tact

Good prognosis

Neurotmesis- Class III

Excessive stretch or laceration

Complete nerve cut

Variable prognosis

Neruon: Soma

cell body where info is integrated

Neuron: Axon Hillock

region where AP is generated

Neuron: axon

transmits information away from cell body

Neuron: dendrites

recieves information and are the main input sites for the neuron

Neuron: Synaptic Terminals

connect neurons and release neurotransmitters into synaptic cleft