neurons, synapses and signaling

Question 1

What are the 5 properties of neurons?

Answer 1

1) receive conducting and then transmitting neurons

2) excitable (we can elicit a response)

3)longevity (function for the lifetime of an organism)

4) amitotic (neurons are located in Go), In some areas with stem cells, they can be replenished

5)high metabolic rate (needs high o2, high gluc to produce a lot of ATP)

Question 2

parts of a neuron

Answer 2

Cell body/soma: contains nucleus, organelles, have extensive rough ER

mature neurons lack centrioles

Dendrites: extensions on the cell body that receive inputs, have high surface area

Axons hilock: base of hte axon (connects cell body and axon). Conducts signals, axons have cytoplasm

Question 3

movement of substances within a neuron (anteriograde vs retrograde)

Answer 3

anteriograde: away from the cell body (mitochondria, cystoskeletal elements, vesicles that renew plasma membrane, enzymes)

retrograde: towards the cell body (organelles that need to be broken down)

intrracellular communications allows cell body to know status of axon termionals

Some signals can activate nuclear genes to promote growth

Question 4

[Neuroglia - CNS] What are Astrocytes? How abundant are they? What do they do (4 things)? What is the blood brain barrier permeable eto

Answer 4

Most abundant, have
1) perivascular feet that contact the blood capillaries. (This stimulates them to form a tight protective seal - blood brain barrier).
2) monitor neuron activity which leads to dilation and constriction of blood vessels
3) regulate composition of tissue fluids by uptaking H+ and neurotransmitters. Prevents things from reaching a high concentration.
4) scar tissue forms where damaged neuron was

Blood brain barries forces things leaving the blood to pass through the cells and not in between so that theres more regulation

permeable to glucose, gases, and things like alcohol, caffeine nicotine. Impermeable to chemotherapies

Question 6

[Neuroglia - CNS] ependymal cells

Answer 6

ciliated and (like central cavities of brain and spinal cord) form a permeable barrier between cerebrospinal fluid that fills these spaces

cilia of ependymal cells circulates this fluid

Question 7

what does cerebrospinal fluid do? (3 things)

Answer 7

1) Protects brain from injury
2) offers chemical stability
3) increases buoyancy which helps cushion brain and spinal cord.

Question 8

[Neuroglia - CNS] Oligodendrocytes

Answer 8

Insulate neural fibers with a covering called a myelin sheet

(helps propagate nerve signals along the fiber. Think saltatory conduction)

Question 9

[Neuroglia - CNS] Microglia. WHat are they?

Answer 9

They are small macrophages that develop from monocytes

1) Wander through CNS and put out projections to sense for things that shouldn’t be there

2) we expect to see increase microglia in areas of infection or trauma. Microglia are important bc cells of immune system have limited access to CNS.

Question 10

[Neuroglia - PNS] Satellite

Answer 10

regulates chemical environment (O2, Co2, nutrients and neurotransmitters)