SLHS 505 Neuroanatomy Quiz 1

What are the two main nervous systems?

1. Central Nervous System

2. Peripheral Nervous System

What are the components that make up the central nervous system?

• Brain + Spinal Cord

• Olfactory and Optic Cranial Nerves (CN I, II)

What are the components that make up the peripheral nervous system?

• cranial nerves and spinal nerves

• autonomic nervous system

• somatic nervous system

What makes up the autonomic nervous system?

Heart muscle, smooth muscle, glands

What are the two divisions of the autonomic nervous system? What are their respective functions?

• Parasympathetic Division

  • Rest and Digest → functions are slow and relaxed, we are chilling!

• Sympathetic Division

  • Fight or Flight → activated to keep us safe, allows us to be active and alert

What does the somatic nervous system control?

voluntary skeletal muscle

What type of section divides structure into front and back portions?

Coronal (frontal section)

What type of section divides structure into into left and right portions?

sagittal (lateral) section

What type of section divides structure into upper and lower portions?

Transverse (horizontal) section

what directional term means: from a high position?

Superior (cranial)

what directional term means: from a low position?

inferior (caudal)

what directional term means: toward the stomach?

anterior (ventral)

which directional term means: toward the back?

Posterior (dorsal)

what directional term means: away from the body’s midline?

lateral

what directional term means: toward the body’s midline?

medial

what directional term means: point nearest limb’s attachment?

proximal

what directional term means: point farthest from limbs attachment?

Distal

what directional term means: toward the outer surface?

peripheral

what directional term means: towards the center

central

what directional term means: on the same side?

ipsilateral

what directional term means: on the opposite side?

contralateral

What does it mean to adduct?

structures come together (adding them together!)

what does it mean to abduct?

structures move apart

What are the components of a neuron?

1. Dendrites

2. Cell Body

3. Nucleus

4. Axon

5. Nodes of Ranvier

6. Myelin Sheaths

What do the dendrites do?

receive the electrical signal and send the information down to the cell body

Can synapses only happen on the dendrites?

No! Synapses can occur directly onto the cell body from other neurons.

What does the axon do?

the axon carries an action potential down and away from the cell body on to the next neuron

What are nodes of ranvier and what is their function?

These are gaps along the axon that are not covered in myelin. These areas contain proteins called ion channels that concentrate at these nodes.

They help regenerate and boost the action potential so that it reach the end of the axon

What happens if these ion channels at the nodes of ranvier aren’t functioning as they should?

It messes up the electrical signaling! The action potential isn’t able to travel down the axon. Leads to some neurogenic communication disorders.

What makes myelin?

oligodendrocytes/oligodendroglia

What is the purpose of the myelin sheath?

it wraps around parts of the axon and aids in conducting the action potential

What kind of autoimmune disorder attacks myelin and how?

Multiple Sclerosis is know for degrading the myelin sheath on neurons by attacking and damaging the oligodendrocytes that produce it. Causes problems in getting that action potential down the axon quickly or even at all.

Where are neurons located and what functions do they carry out?

• located in the CNS and PNS

• communication with nervous system and with organs, muscles, and glands

What are the 5 types of glial cells?

• Astrocytes

• oligodendroglia

• microglia

• schwann cells

• satellite cells

Where are astrocytes located and what functions do they carry out?

• located in the CNS

• maintain neural environment (blood brain barrier) → keeps a seal and prevents harmful things from crossing into our brain

• repair/feed neurons

• modulate neural transmission

• modulate breathing

Where are oligodendrocytes located and what functions do they carry out?

• located in the CNS

• produce myelin

Where are microglia located and what functions do they carry out?

• located in the CNS

• scavenge debris and defend against foreign substances → CLEAN UP CREW!

What happens to microglia in neurological diseases?

They become abnormally active in things like alzheimers and parkinsons

• trigger inflammation

What are upper motor neurons?

neurons that sit up in the brain in the primary motor cortex

• send electrical signals/descending input down to the spinal cord for voluntary movement

What are lower motor neurons?

motor neurons that sit in the spinal cord and send axons out to muscle

Where do cell bodies live in the spinal cord?

they live in the anterior horn/ventral portion of the spinal cord

What is ALS?

• Amyotrophic lateral sclerosis – ALS

  • Characterized by the death of upper motor neurons in the cortex, brain stem, and spinal cord 

    • Caused by genetic mutations and some environmental causes but we don't know much about it

    • Someone who has death of motor neurons in the brain they will have problems planning and initiating speech 

      • In the brain stem we have motor neurons that are important for swallowing, breathing, tongue movement 

        • These cell bodies dying means peoples speech gets worse – progressive – it only gets worse 

    • A few glial cells involved here – contribute to inflammation 

      • Neurons shrink and die - muscles lose the signal from the neuron

    • Swallowing and speech deficits can start at the beginning bc of neuron death in brain stem – but not the case for everyone – there are different forms of ALS

    • There are prosthesis that help people with ALS speech once they lose their ability to do so

What are the segments of the spinal cord?

• cervical — head and neck

• thoracic — trunk/chest

• lumbar — legs

• sacral — but

what do the disks between vertebrate bones do? What happens with they start to degenerate?

Discs between vertebrate bones help mobility and provide joint support → Shock absorbers

• degenerative discs can cause compression of spinal nerves

What do spinal nerves do?

• Spinal nerves emerge from segments of the spinal cord. They carry sensory information about pain, touch, temperature into the spinal cord and motor information out of the spinal cord to the muscles

Afferent v Efferent

• Afferent – sensory signals from the PNS which move from the periphery of the body through spinal nerves to the central nervous system (spinal cord, brain)

• Efferent: motor signals which move from the CNS to the periphery of the body (PNS)

How does the knee jerk reflex work?

• Pathway 1: Sensory info

(afferent) from tapping the

knee is picked up by

quadriceps (extensor)

muscle (afferent) which

sends signals to motor

neurons in the spinal cord.

These motor neurons send

excitatory signals (efferent)

onto quadriceps muscle to

contract

• Pathway 2: Sensory info

(afferent) from quadriceps

muscle due to tap on knee

goes directly to interneurons

in the spinal cord.

Interneurons send signals to

motor neurons (efferent) that

tell the hamstring (flexor)

muscle not to contract

(inhibits it; this is the

opposing muscle)