EXAM 1 - Lecture 1-8

The CNS is composed of two primary structures...

Brain and Spinal Cord

Name the 3 components of the Brain

Cerebellum ( 2 hemispheres + diencephalon)

Cerebellum

Brain Stem: Bridge to Spinal Cord

Nucleus

collection of neurons in CNS

Identify the Major Components of the brain

A. Cerebrum

B. Diencephalon

C. Cerebellum

D. Brainstem

What is the function of the brainstem?

Bridge to spinal cord

What are the two sets of nerves of the PNS?

cranial nerves and spinal nerves. Sensory and Motor Ganglia

What is a collection of neurons in the PNS?

ganglion

Cranial Nerves go out of...

brain

Spinal nerves go out of...

spinal cord

What are the 3 planes to view the brain

Horizontal, Coronal, Sagittal

Which of the 3 planes is most commonly used for MRI?

Horizontal view

What are all the directions across the Brain?

Ventral (inferior) : Toward Stomach

Dorsal (superior) : Toward back

Anterior (rostral): In front

Posterior (caudal): In back

(T/F) All animals have superior and inferior planes

FALSE. Since we stand up straight we only have superior and inferior

What are the planes across animal?

Dorsal = Back

Ventral = stomach

Rostral = toward nose

Caudal = toward ass

Where does the cerebellum sit on the brain?

Dorsal part of brain

(T/F). You can see the cerebellum from the dorsal view in ALL animals

FALSE. you cannot see the brain in dorsal view for higher apes and humans. Rest of animals you can

The Brainstem includes...

pons + medulla

The Hindbrain is made of...

brainstem (pons + medulla) and cerebellum

The forebrain is made of...

cerebral hemispheres + diencephalon

How many cervical nerves are there?

8 (C1-C8)

Are sensory neurons afferent or efferent?

afferent so they carry info towards the CNS

Are motor neurons afferent or efferent?

efferent so the carry info away from CNS

Sensory and motor neurons are fall into a group called....

spinal nerves (cranial nerves not covered)

What are the two types of SENSORY root ganglion

Dorsal Root ganglion: for body; only spinal nerves

Cranial ganglion: for head; only cranial nerves

What does the motor root ganglion control?

Autonomic Nervous System:

Sympathetic NS : Fight or Flight

Parasympathetic NS: Rest and Digest

What does ipsilateral mean?

same side

What does contralateral mean?

opposite side

What are these structures of the neuron:

Soma

Dendrite

Axon

Synapse

Myelin Sheath

Nodes of Ranvier

Soma: Cell body

dendrite: receive transmission

axon: transmit signal ( 1 per neuron)

synapse: contact point between neuron

myelin sheath: covering around axon

Nodes of ranvier: gaps between myelin sheath

afferent

toward CNS

efferent

away from CNS

Commissure

any collection of axons that connect one side of the brain with the other side (SAME LEVEL)

Decussation

crossing of the midline that occurs in many tracts so that brain senses and controls contralateral side of body (DIFFERENT LEVEL)

(T/F). Commissure occurs at same level

True

(T/F). Decussation occurs at same level

False. Different levels

What do you call axon bundles travelling in CNS?

Tract

What do you call axon bundles travelling in PNS?

Nerves

What is white matter?

myelinated axons

What is grey matter?

cell bodies

In the Brain, (white/grey) matter surrounds (white/grey) matter

In the Brain, grey matter surrounds the white matter

In the Spinal cord, (white/grey) matter surrounds (white/grey) matter

In the Spinal cord, white matter surrounds grey matter

Soma

cell body of a neuron

Dendrites

receive messages from other neurons

Synapse

A junction where information is transmitted from one neuron to the next.

How many axons does a neuron have?

one

Nissl bodies

RER in neurons -- synthesize enzymes (e.g., ChAT) and peptide neurotransmitters.

multipolar neuron

A neuron with a single axon and multiple dendrites; the most common type of neuron in VERTEBRATES

bipolar neurons

A neuron that has only two projections (one axon/one dendrite) from the cell body

What are the given examples of Bipolar Neurons?

Spiral ganglion of auditory system

olfactory epithelium

Bipolar neurons in retina

pseudounipolar neurons

starts as a bipolar neuron; has two processes that merge into one.

Process one: axon --> cell body

Process two: cell body ---> axon

When are pseudounipolar neurons used?

Spinal Dorsal root ganglia --- sensory information

unipolar neuron

a neuron with one process extending from its cell body

ONLY in invertebrates

(T/F) Lower Motor Neurons end directly on muscles, glands, and effectors

TRUE

(T/F) Upper Motor Neurons end directly on muscles, glands, and effectors

False. The UMN is the general. The LMN is the soldier. UMN only tells the LMN what to do.

Which neuron is the most abundant in nervous system

Interneurons

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory neurons and motor neurons

What are the two types of interneurons?

local and projection

Local interneurons: locally interconnect other neurons, confined to small area

Projection Interneuron: Long axes connecting different areas

local interneurons

Local interneurons: locally interconnect other neurons, confined to small area

projection interneurons

Projection Interneuron: Long axes connecting different areas

(T/F). Interneurons are key in reflex arc

TRUE

Another name for the cell membrane in neurons is...

neurolemma

polyribosomes

free floating ribosomes

What are the 3 components of the NEURAL cytoskeleton

Microtubules, Neurofilaments, Microfilaments

(T/F). The Neural cytoskeleton is static

False. Very fluid

Microtubules are ____(large, small, middle) and made of_____ proteins

Large and made of tubulin proteins

Neurofilaments are ____(large, small, middle) and made of_____ proteins

Middle and made of family of cytokeratin proteins

Microfilaments are ____(large, small, middle) and made of_____ proteins

small and made of actin

What is the function of microtubules in the neuron?

transport large organelles

What is the function of neurofilaments in the neuron?

support and maintain shape of neuron

What is the function of microfilaments in the neuron?

anchor membrane proteins

What are the 3 parts of the axon structure?

Axon Hillock: Beginning

Axon Proper: Middle

Axon Terminal: End

Nissl bodies are found everywhere in the neurons but ____

Axon Hillock

(T/F). The ER extends into the axon

False it does not. It's the greatest difference between the axon and soma

What is the "initial segment" in neurons?

starting point of Action potential

high concentration of Na+ channels

What does the "initial segment" lack?

no rER found here. (Rough ER)

anterograde transport

soma ---> axon terminal

retrograde transport

axon terminal ---> soma

Anterograde transport facilitated by ____ ,which is a cytoskeletal protein of ____

Kinesin, Microtubules

Retrograde transport facilitated by ____ ,which is a cytoskeletal protein of ____

Dynein, Microtubules

Retrograde & Anterograde transport are (FAST/SLOW) transport

FAST

The axon terminal has a large number of ____ to support the energy demands of neurotransmitter transport

mitochondria

What are 4 types of synapses and their direction of travel?

Axosomatic: Axon --->soma

Axodendritic: Axon --->dendrite

Axoaxonic: Axon ---> Axon

Dendrodritic: Dendrite ---> Dendrite

(T/F). All synapses use chemical neurotransmitters.

FALSE. Dendrodendritic use electrical synapses

What glial cells are found in the CNS?

oligodendrocytes, astrocytes, microglia, ependymal cells

What is the role of oligodendrocytes?

myelination in CNS

What is the most abundant glial cell in the CNS?

astrocyte

What is an astrocyte?

glial cell in CNS

Provide nutrition to neurons

clears out neurotransmitters in synaptic cleft

What glial cell forms the blood-brain barrier?

astrocytes

What is K+ spatial buffering?

astrocytes digest extracellular K+ pumped out

1 oligodendrocytes myelinate ___ axon segement (s).

1 Schwann cell myelinate ___ axon segment

Oligodendrocytes = several

Schwann cells = one

What do satellite cells do?

support neurons in PNS

Under what condition will an axon in the PNS be wrapped by several Schwann cells?

unmyelinated axon so conduction is slow

microglial cells

glial cell in CNS that digest waste

Can act as phagocytes

What is role of ependymal cells?

Produce cerebrospinal fluid (CSF)

Ependymal cells work with ____ to generate CSF

Choroid plexus

How is electric current generated in neuron?

movement of ions

How do ion channels and ion pumps differ?

Ion channel: control resting and action potential

Ion pump: consume ATP to drive movement of ions

What are the major properties of ion channels?

1. Ion Selectivity

2. Ion permeability

3. Gating property

Ion channels allow movement ___ gradient

Ion pumps allow movement ___ gradient

Ion channels: Down

Ion pumps: Against

What ion channel maintains resting membrane potential?

K+ leak channels

Diffusion of K+ across neuron membrane maintains negative charge within neuron

What ion pump re-establishes resting membrane potential after Action potential?

Na+/K+ Pump

3 Na+ out

2 K+ in