Final Exam Flashcards

What are the three main components of a homeostatic response?

1. Receptor (Skin)

2. Control Center (Brain)

3. Sensor/Effector (Shivering)

How does the nervous system carry out tasks?

1. Receive information

2. Process information

3. Respond

What are the universal properties of neurons?

• Excitability (irritability)

• Conductivity

• Secretion (chemical neurotransmitter)

Excitability

Responsiveness

Conductivity

Transmission of signal

Secretion

Production of neurotransmitters (ACH)

(IMAGE) → Subdivisions of the Nervous System

Central Nervous System (CNS)

(IMAGE) → Subdivisions of the Nervous System

Peripheral Nervous System (PNS)

Central Nervous System (CNS)

Control Center → Goes to the brain.

• Thoughts, emotions, feeling

Peripheral Nervous System (PNS)

Sensory/Afferent Division → Carries information to the CNS

• Visceral (Signal from internal organ

• Somatic (Signal from skin or muscle)

• Motor/Efferent → Carries information from CNS

Somatic Motor Division

Voluntary motor movements

Visceral Motor Division

Autonomic, Involuntary movements

Sympathetic Division

Fight or flight (Visceral → Autonomic → Automatic)

Parasympathetic Division

Rest or Digestion (Visceral → Autonomic → Automatic)

Sensory (Afferent) Neurons

 Conduct signals from receptors to the CNS -> PNS System

Interneurons

Are confined to the CNS -> CNS System

Motor (Efferent)

Neurons conduct signals from the CNS to effectors such as muscles and glands -> PNS System

Neurosoma

Lots of tough ER (Nissl body) and cytoskeleton; NO CENTRIOLES (DOES NOT DIVIDE CELLS or undergo mitosis) → Contains nucleus!

Axoplasm

Cytoplasm of axon

Axolemma

Plasma membrane of axon

NIssl Body

It makes proteins in neurons → Similar to how ribosomes make proteins

• Repair and maintain

Axon

Long thin fiber that carries information

Each neuron will only have 1 axon

Axon Terminal

End portion of the Axon → Ends

Dendrites

Branches surrounding Nerusoma

Receives electrical impulses and information

(IMAGE)

Trigger Zone

(IMAGE)

Axon Hillock

Trigger Zone

Initiates action potential

Axon Hillock

Initial point of Axon

All impulses

IMAGE

Multipolar Neurons

IMAGE

Bipolar Neurons

IMAGE

Unipolar Neuron

IMAGE

Anaxonic Neuron

Name two divisions of the nervous system

CNS and PNS

Name three functional classes of neurons

Sensory, Interneurons, Motor neurons

Where are interneurons found?

CNS

Is the sensory division afferent or efferent?

Afferent

Name the part of the neuron that receives stimuli?

Dendrites

Name the part of the neuron that releases chemical messengers

Axon Terminal

Nucleus

Cluster of somas (cell bodies) in CNS

Ganglion

Cluster of somas in PNS

Nerve

Bundle of axons in PNS

Neuroglia (Glial)

Supportive Cells, Protects

Non-neuro → Does not conduct electrical impulses

10 Neuroglia = 1 Neuron

Glial Cells in CNS

• Oligodendrocytes

• Ependymal Cells

• Microglia

• Astrocytes

Glial Cells in PNS

• Schwann Cells

• Satellite Cells

Oligodendrocytes

Forms myelin sheath in CNS

Ependymal Cells

Secrete and circulate cerebrospinal fluid (CSF)

Microglia

Blood-brain barrier (BBB)

Astrocytes

Immune defense

Schwann Cells

Form myelin

Satellite Cells

Supports neuron

Myelin

White-greish matter that protects and cushions the axons of neurons

Mylein Sheath (PNS)

Distance from axon to the end of the myelin is known as the myelin sheath

• Contains neurilemma

• Schwann Cell forms myelin

• Impulses are faster

Neurilemma

Outermost covering of the myelin sheath

Mylein Sheath (CNS)

Distance from axon to the end of the myelin is known as the myelin sheath

• No neurilemma

• Oligodendrocyte myelinates several nerve fibers

• Impulses are slowe

Regeneration of a damaged peripheral nerve fiber

In order for regeneration to happen, you need neurilemma and Schwann cell -> Only happens in PNS because it contains both, CNS doesn’t

• Oligodendrocytes have growth inhibiting proteins

What is the functional difference between a dendrite and an axon?

Dendrites → Receives information, impulses, electrical signals, stimuli

Axon → Carries the information

How are oligodendrocytes and Schwann cells similar? How are they different?

1. Similar

2. One has neurilemma and Schwann cells, other doesn’t. One is fast, one is slow.

• dendrites detect, axons react

Mature neurons rarely undergo mitosis, so where do brain tumors come from?

Glial (Neuroglia 10 = 1 neuron) Cells

Brain tumors arise from?

• Meninges

• Metastasis from tumors in other organs

• Often glial cells that are mitotically active throughout life

Metastasis

Process by which cancer cells spread from their original (primary) site to other parts of the body and form secondary tumor

Treatment of Tumors

• Gliomas (tumors) grow rapidly and are highly malignant

• Blood-brain barrier decreases effectiveness of chemotherapy

• Treatment consists of radiation or surgery

Multiple Sclerosis

• Myelin is compromised

• Oligodendrocytes and myelin sheaths replaced by hardened scar tissue

• Nerve conduction disrupted (double vision, tremors, numbness, speech defects)

• Cause may be autoimmune triggered by virus

Tay-Sachs disease

A hereditary disorder of infants of Eastern European Jewish ancestry

• Defective gene on chromosome 15

• Abnormal accumulation of glycolipid called GM2 in myelin sheath

  • Blindness, loss of coordination, and dementia

  • Fatal before age 4

The integrative functions of the nervous system are preformed maily by

a)

b)
c)

d)

e)

E

The glial cells that fight infections in the CNS are

a)

b)
c)

d)

e)

A

Schwann cells produce layers of membrane containing myelin, which provides nutrition for the dendrites

a) 

b)

B

Motor axons cannot regenerate after peripheral nerve injury

a)

b)

B

Muscle atrophy occurs during early regeneration of nerve fibers

A

Local potential

• Stimuli include chemicals, light, head, or mechanical

• A chemical stimulant binds to a receptor on the neuron (dendrites/soma)

• Na+ gates open; a current travel toward the cell’s “trigger zone”

On the graph, local potential may go back down. If the impulse isn’t strong enough it will return to RMP, however if it is, action potential will be carried through

Refractory

No response to stimuli

The absolute and relative refractory period (Add image)

• A period of resistance to stimulation

• Two phases:

  • Absolute Refractory and Relative Refractory

• Only a small patch of neurons membrane is refractory at one time

Conduction speed or nerve fibers

• Signal conduction occurs on the surface of a fiber so speed depends on two factors:

  • Diameter of fiber

  • Presence or absence of myelin

Unmyelinated Nerve Fibers

• no insulation, no protection, no cover

• Present in both CNS and PNS

Which ion has the greatest effect on RMP: K+ or Na+

K+ Potassium

Where on a neuron does a local potential occur?

Dendrites and/or soma

What part of the neuron does the local potential have to reach in order to trigger an action potential?

Axon hillock

Define refractory period

Period of resistance to stimulation

T or F. A very strong stimulus can cause another AP during relative refractory period

True

What is mylein

A fatty layer of insulation around the axon

Synapses

Junction (link) between 2 neurons

Chemical Synapse

Junction (link) between 2 neurotransmitters.

• Presynaptic axon terminal

• Synaptic Cleft

• Postsynaptic Membrane

What is a neurotransmitter?

Four major categories: Acetylcholine, Amino Acids, Monoamines, Neuropeptides

Example: ACH

ACH

Muscle contraction/control/memory

Amino Acids

Fast synaptic response

Example: GABA, Glutamic Acid

Monoamines

Food, arousal, pleasure, etc.

Exmaple: Dopamine

Neuropeptides

Pain, emotion, appetite

Example: Enkephalin, Substance P

Neural integration

The ability to process, store, and recall information and use it to make decisions

Works by summation:

• EPSP + IPSP

• Temporal

• Spatial

EPSP

Excitory(depolarization)

IPSP

Inhibitory(hyperpolarization)

Temporal

Multiple Signals arrive from pre-synaptic to post-synaptic

Spatial

EPSP + IPSP

Synaptic plasticity

The ability of synapses to change

Kinds of memory

Immediate, short, and long-term memory

Immediate Memory

• Ability to hold something in your thoughts for a few seconds

• Briefest kind of memory

• Holds information for present

• No structural change in brain

• Does not require protein-synthesis

Short-term Memory

• STM- lasts a few seconds-minutes

• Includes working memory

• Holds information for present but longer than immediate memory

• Structural change in brain but not drastically

• Does not require protein synthesi

Long-term memory

• Days to year

• Permanent change

  • Formation of new synapse

  • Growth of dendrites

• Does require protein-synthesis

  • 2 types: Explicit and Implicit

Explicit

Events you can put words into

Implicit

Reflexive or unconscious memory

How do we forget?

NO:

1. Formation of new synapse

2. Growth of dendrites

Alzheimer Disease

• Deficiencies of ACh and nerve growth factor (NGF)

• Diagnosis confirmed at autopsy

  • Atrophy of gyri (folds) in cerebral cortex

  • Formation of B-amyloid protein from breakdown product of plasma membranes

Treatment:

• Do not have any real treatments, what they did have caused serious side effects