Bio 25: Eder - Ch. 12-15

Peak of action potential depolarization

+30 mV

Size of a positive graded potential

+5 mV

Medulla oblongata

- contains cardiovascular and respiratory rhythmicity centers - contains sensory and motor nuclei of cranial nerves 8-12 - relays sensory and motor information

Pons

- contains sensory and motor nuclei of cranial nerves 5-8 - pneumotaxic centers (adjust activity of respiratory centers in medulla) - major junction for info to and from cerebellum - relays sensory and motor information

Size of a negative graded potential

-5 mV

Threshold

-60 mV

Resting potential

-70 mV

Hyperpolarization

-90 mV

Which of the following correctly describes a nerve?

A bundle of axons in the peripheral nervous system

What is an action potential?

A large, rapid, "all or nothing" electrical signal that moves down the axon

What is a graded potential?

A small change in membrane potential, can be excitatory or inhibitory

The anterior portion of the brain that contains motor and pre-motor areas is the:

Frontal lobe

How does a neuron reach threshold?

Graded potentials build up

What is the purpose of myelin?

It insulates the axon and increases the speed of electrical signals

At rest, what does the Sodium Potassium Pump (Na/K - ATPase) do in a neuron?

It moves 3 sodium OUT of the cell for every 2 potassium INTO the cell

Where is the endoneurium found?

It surrounds the un-myelinated or myelinated axon

The spinal cord ends near the level of _________________ leaving the remaining spinal nerves to fill the space as the _____________________

L1 : cauda equina

Which of the following receptor types is most commonly used for somatic sensation?

Mechanoreceptors

During the _____ , the membrane is hyperpolarized and sodium channels begin to recover - if a strong stimulus is received a second action potential may occur

Relative refractory period

Skin, muscle and joint sensation is classified as _____ , while eye, ear, tongue, nasal epithelium sensation is classified as _____

SOMATIC: SPECIAL

What does it mean for a sensory pathway to be AFFERENT?

Sensory signals are input FROM the peripheral nerves traveling TO the CNS

Which ions are most important in determining electrical potential?

Sodium and potassium

What happens when a neuron is stimulated?

Sodium ions enter the cell

At rest, what is the state of the sodium and potassium concentration (chemical) gradients

Sodium is more concentrated outside, potassium is more concentrated inside

What is the difference between a somatic motor pathway and an autonomic motor pathway?

Somatic targets are skeletal muscles, autonomic targets are organs

Which of the following sensations involves a somatic sensory pathway?

Touch

How is the membrane potential measured in a neuron?

Units of voltage

What bones protect the spinal cord?

Vertebrae bones

What type of channels are opened during the hyperpolarization phase of an action potential?

Voltage gated potassium channels

What type of channels open to cause REpolarization?

Voltage gated potassium channels

What type of channels are opened when a neuron reaches threshold?

Voltage gated sodium channels

What type of channels open to cause DEpolarization?

Voltage gated sodium channels

Where does the cerebrospinal fluid drain to return to the blood supply?

arachnoid villi to the venous sinuses

Which neuroglial cells surround the capillaries to form the blood brain barrier?

astrocytes

Anti-cholinergic medications block muscarinic acetylcholine receptors and will directly _____

block the parasympathetic nervous system at the target organ

The Central Nervous System (CNS) is composed of the _____

brain and spinal cord

The output to skeletal muscle, organs and glands uses the following pathway

brain: spinal cord : motor neuron : skeletal muscle

Cerebellum

cerebellum = controlling movement! (posture and movement pattern)

Mesencephalon (midbrain)

contain corpora quadrigemina - these are responsible for reflexes due to light and sound

Starting with the outmost layer, name the layers of meninges that protect the brain:

dura mater; arachnoid mater; pia mater

Which neuroglial cells line the ventricles to form cerebrospinal fluid?

ependymal cells

Special sense organs

eyes, ears, skin, mouth, and nose

A patient is unable to contract the quadriceps and fails to respond to the patellar reflex test - which nerve is affected?

femoral nerve

Astrocytes

forms blood brain barrier - structural support and neurotransmitter exchange

Oligodendrocyte

forms myelin sheath around axons in the central nervous system

Schwann cell

forms myelin sheath around axons in the peripheral nervous system

Which of the following is a typical SYMPATHETIC pathway?

hypothalamus: spinal cord: SHORT preganglionic neuron: ganglion: LONG postganglionic neuron to organ

Parasympathetic ganglia are located _____ , while sympathetic ganglia are located _____

in the organs: near the spinal cord

What causes the cervical enlargement of the spinal cord?

large number of connections to and from the arm

What is the pathway of cerebrospinal fluid through the brain?

lateral ventricles; 3rd ventricle; cerebral aqueduct; 4th ventricle

Which area of the brain contains reflex centers for cardiovascular, respiratory, swallowing and sneezing?

medulla oblongata

Which regions make up the brainstem?

midbrain, pons, medulla oblongata

Ependymal cells

monitors and maintains composition of cerebrospinal fluid

What type of synapse listed below is found in a somatic motor pathway?

neuromuscular junction

A group of cell bodies found in the central nervous system is called a _____________, a group of cell bodies found outside the central nervous system is _______________

nucleus: ganglion

What is the "rest and digest" branch of the Autonomic Nervous System?

parasympathetic nervous system

Which nerve is located near the cervical plexus and innervates the diaphragm?

phrenic nerve

Which layer of meninges surrounding the spinal cord is the deepest, found directly touching the spinal cord?

pia mater

Sciatic nerve pain would be found:

radiating down the posterior thigh

Follow a somatic sensation from receptor to brain. Which example pathway is correct?

receptor: sensory neuron: dorsal root: spinal cord: thalamus: somatosensory cortex

Microglia

removes cellular debris and pathogens

Vagus nerve

responsible for 75% of parasympathetic outflow (heart, lungs, intestines, etc)

The dorsal (posterior) root ganglia of the spinal cord contain ______________________

sensory neuron cell bodies

The sensation of the skin such as touch, pressure, temperature is a _____ pathway of the peripheral nervous system

sensory, afferent

What is found in the VENTRAL HORNS of the spinal cord?

somatic motor neuron cell bodies

Satellite cell

surrounds cell body and regulates nutrient and waste composition

When the body is undergoing or preparing for physical activity, stress or threatened, which of the following will occur?

sympathetic activation: increased heart rate and airflow, decreased digestion

Stressors tend to activate the _____________________

sympathetic nervous system

When activated, the sympathetic nervous system redirects blood to:

the brain, heart and skeletal muscle to be able to "run away"

The SYMPATHETIC nervous system has major output from the _____ regions

thoracic spinal cord and lumbar spinal cord

A patient reports numbness in the pinky finger and difficulty spreading the fingers outward and inward - which nerve is affected?

ulnar nerve

During the _____ , all sodium channels are either engaged or inactivated - no further action potentials can be stimulated

Absolute refractory period

Where is the difference in electrical charge located in a neuron?

Across the plasma membrane

Where does the action potential travel?

B Down the length of the axon

Beta-blockers are common medications prescribed to decrease heart rate, and they act via blocking the action of B-adrenergic receptors in the heart. Explain.

Beta blockers prevent epinephrine from increasing heart rate

Which of the following contains sensory receptors?

Blood vessels, ears, eyes, organs, and skins

What are the major components of the nervous system?

Brain, spinal cord, and nerves

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons Acetylcholine

Which portion of a neuron receives input from other cells?

Dendrite

How do neurons communicate?

Electrical potential changes at the membrane

The spinal cord cannot signal or receive signals to/from sensory and motor pathways without the brain

False

What material is found wrapped around axons?

Myelin

Which part of the neuron would you expect to see if you looked at WHITE MATTER under a microscope?

Myelinated axons

The primary excitable cell in the nervous system is the _____

Neuron

What is the primary cell of the nervous system?

Neuron

What are the targets of the autonomic nervous system?

Organs

Which lobe contains the post-central gyrus and somatosensory areas?

Parietal lobe

Which of the following descriptions would use an action potential for signaling in the nervous system.

The sensory neuron sends a signal to the spinal cord A motor neuron sends a signal from the spinal cord to a muscle