Lesson 5: Brain Anatomy

Question 1

What is a receptor protein?

Answer 1

A protein that is sensitive to and capable of communicating some signal
- either ionotropic or metabotropic

Question 2

What is an ionotropic receptor?

Answer 2

A receptor protein that is an ion channel. The properties of the pore of the ion channel determine if it will produce ESPSs or IPSPs
- turn toward ions to mediate their effects

Question 3

What is a metabotropic receptor?

Answer 3

A receptor protein that is not an ion channel. These receptors typically trigger an intracellular signaling cascade that involves g proteins, which can produce a vairety of cellular effects
- turn toward metabolism to mediate their effects

Question 4

How are g proteins activated?

Answer 4

By metabotropic receptors

Question 5

What molecules do g proteins use?

Answer 5

GTP molecules (instead of ATP molecules) for the energy they need to perform chemical reactions

Question 6

When is a g protein “on”? When is a g protein “off”?

Answer 6

A g protein is on when:
- g protein is bound to GTP (can trigger chemical reactions)
- g protein lets go of GDP
A g protein is off when:
- g protein converts GTP to GDP
- g protein is still bound to GDP

Question 7

How does a metavotropic g protein receptor cause an ion channel opening?

Answer 7

1. Neurotransmitter binds to a metabotropic receptor
2. Activated g proteins transmit the message intracellularly
3. Some ion channels are gated (directly or indirectly) by activated (“on”) g proteins

Question 8

What does g-protein signaling cascades do?

Answer 8

1. Opening g-protein gated ion channels
2. Changes in gene transcription
3. Secretion of substances from the cell
4. Anything the cell wants

Question 9

Where can synapses form?

Answer 9

1. Between axon terminals
2. Dendrites (dedritic shafts)
3. Dendritic spines
4. The soma (cell body)
5. Other axon terminals (axoaxonic synapses)

Question 10

Where do synapses for to cause an action potential?

Answer 10

1. Dendrites (dendritic shafts)
2. Dendritic spines
3. The soma (cell body)

Question 11

What are axoaxonic synapses?

Answer 11

They regulate the amount of neurotransmitter that the second neuron will release when it has an action potential

Question 12

What is presynaptic inhibition? Presynaptic facilitation?

Answer 12

Presynaptic inhibition: hyperpolarizing the axon terminal so that the voltage-gated calcium channels will not open at all (or for very long)

Presynaptic facilitation: depolarizing the axon terminal so that the voltage-gated calcium channels are more likely to open

Question 13

What is an autoreceptor?

Answer 13

Detects the neurotransmitter that the cell is releasing
- generally metabotropic and inhibitory
- main source of presynaptic inhibition

Question 14

What is the neuraxis?

Answer 14

The line that can cut an individual in half

Question 15

What are all the anatomical directions and what do they mean?

Answer 15

Anterior/Rostral: in front/beak
Posterior/Caudal: behind/tail
Superior/Dorsal: above/back
Inferior/Ventral: below/belly

Question 16

What are the three types of planes of the brain?

Answer 16

Transverse (coronal): cutting banana
Sagittal: split brain surgeries
Horizontal: cutting onion

Question 17

What does medial and lateral mean?

Answer 17

Medial: toward midline
Lateral: away from midline

Question 18

What is contralateral and ipsilateral?

Answer 18

Contralateral: structures on the opposite side of the body (ex: right brain controls left hand, etc.)
Ipsilateral: structures on the same side of body (ex: taste and smell)

Question 19

What is brain nuclei?

Answer 19

In the brain, the word nuclei means a collection of neurons that are clustered together that all work together to serve some function

Question 20

What are the two parts of the nervous system?

Answer 20

Central nervous system (CNS) and the Peripheral nervous system (PNS)

Question 21

What are the two types of myelin and where do each belong?

Answer 21

Oligodendrocytes belong in the CNS and Schwann cells belong in the PNS

Question 22

What is the blood-brain barrier and where is it located?

Answer 22

No leakage occurs in the CNS, so nothing can leave from the blood-brain barrier

Question 23

Where does lymph come from and where is it located?

Answer 23

It comes from the blood vessels that release plasma which then becomes lymph
- collects waste
- only in PNS (because of blood-brain barrier in CNS)

Question 24

What are the 3 types of meninges?

Answer 24

1. Dura mater: thick, tough, unstretchable tissue
2. Arachnoid membrane: soft and spongy
3. Pia mater: blood vessels

Question 25

What is the subarachnoid space?

Answer 25

Between the arachnoid membrane and pia mater. It is filled with cerebrospinal fluid (CSF) and blood vessels

Question 26

How is cerebrospinal fluid (CSF) made?

Answer 26

By choroid plexus, a tissue found in each brain ventricle
- CSF if made continuously and it is half replaced every three hours
- it flows from the ventricles around (and into) the brain and spinal cord before it is absorbed into the blood supply

Question 27

What are the neurons of the CNS called?

Answer 27

Interneuron: axons stay local
Projection neuron: axon of a cell goes outside of the area where its soma is lcoated

Question 28

What are the neurons of the PNS called?

Answer 28

Motor neurons: outputs
- efferent fibers: releasing information away from CNS

Sensory neurons: inputs
- afferent fibers: gaining information towards the CNS

Question 29

T/F: Cranial and spinal nerves are a part of the CNS.

Answer 29

False. They are a part of the PNS

Question 30

How is the PNS split up?

Answer 30

Somatic nervous system: interacting with the external world
Autonomic nervous system: interacting with the internal world

Question 31

What are the two divisions of the autonomic nervous sytem efferent branch?

Answer 31

Sympathetic nervous system: fight-flight-freeze response (adrenaline)
Parasympathetic nervous system: rest and digest (relaxed state)