Lecture 1: Intro to the Nervous System

Question 1

The Nervous System anatomically contains two parts:

1.

2.

Explain where the neurons are within each

Answer 1

Nervous System contains two parts:

1. Central Nervous System (CNS): Comprised of neurons that sit within the confines of the protective layer named Dura
2. Peripheral Nervous System (PNS): contains neurons that are outside of the dura

Question 2

Explain the following anatomical planes:

Coronal

Horizontal

Sagittal

Answer 2

Question 3

What is the difference between a nucleus and a ganglion?

Answer 3

Ganglion is a cluster of neurons that perform the same function… ganglion are located in the PNS

Nucleus are located in the CNS

Question 4

Explain the directions within the Nervous System:

For the Brain

Answer 4

Question 5

Explain the directions in the nervous system:

For the Spinal Cord

Answer 5

Question 6

What are the meninges?

Name the three layers within the CNS

Answer 6

The meninges are a set of three specialized membranes that protect the CNS

CNS Meninges: Dura, Arachnoid, and Pia

Question 7

Explain the CNS Meninges in Detail

Answer 7

Dura Matter: outer layer, tough layer that protects the CNS from penetration

Arachnoid Matter: middle layer, spider like, forms a fluid-resistant sac around the brain and spinal cord

Pia Matter: innermost membrane: very thin and delicate membrane seperated by the subarachnoid space from the arachnoid, the brain’s CSF flows within this space

Question 8

Within which layer does the brain’s fluid and CSF reside?

Answer 8

The brain’s CSF resides within the space between the arachnoid and pia matter…called the subarachnoid space

Question 9

Explain the set of analogous meninges in the PNS

Answer 9

CNS: Dura, Arachnoid, Pia

PNS: Epineurium, Perineurium, and Endoneurium

Question 10

Explain the dura mater

Answer 10

Dura matter: outer layer, tough layer that protects the CNS from penetration

Question 11

Explain the arachnoid mater

Answer 11

Arachnoid mater: middle layer, spider like, forms a fluid-resistant sac around the brain and spinal cord

Question 12

Explain the pia mater

Answer 12

Pia mater: not visible to the naked eye…innermost membrane, very thin delicate membrane seperated by the subarachnoid space from the arachnoid..

the CSF flows in this space

Question 13

Cerebral Spinal Fluid (CSF)”

• Normal volume is roughly _____ mL, most is in the _________
• Secreted at a rate of _____ per day
• Explain the composition of CSF in respect to protein, glucose, and RBCs

Answer 13

CSF:

• Normal volume is roughly 150 mLs, most is within the subarachnoid space
• Secreted at a rate of 500 mL per day (passive diffusion from blood and active transport from ependymal cells)
• Composition: much lower protein than serum blood, glucose slightly higher, virtually no RBCs

Question 14

CSF:

• How can it be used diagnostically?
• How do clinicians obtain samples?

Answer 14

Cerebral Spinal Fluid:

Deviations in its composition is very useful diagnostically

Samples are obtained via a spinal lumbar puncture (L2-L5)

Question 15

List the functions of the CSF:

1.

2.

3.

Answer 15

Functions of Cerebral Spinal Fluid:
1. Maintains a constant enviornment for neurons and glia by regulating ionic concentrations, pH, and glucose

2. Removes harmful metabolites from circulation
3. Provides a protective hydraulic suspension system for the brain

Question 16

How much protein is within the CSF vs the blood?

Answer 16

CSF only has 35 mg/dL of protein

The blood has 7000 mg/dL

Question 17

Both the ____ and the _____ are contained within the skull, whereas the spinal cord is contained within the ______

Answer 17

Both the forebrain and the brainstem (midbrain and hindbrain) are contained within the skull

The spinal cord is contained within the vetebral column

Question 18

The forebrain is divided into two sections:

1.

2

which are further divided up as…..

Answer 18

Forebrain:

1. telencephalon
2. diencephalon

Telencephalon: cerebral cortex, striatum and pallidum, and the amygdala

Diencephalon: thalamus and hypothalamus

Question 19

What are the core elements of the basal ganglia?

Answer 19

The core elements of the basal ganglia are striatum and pallidum

Question 20

Draw a cross-section of a brain and label the following components:

cerebral cortex, corpus callosum, thalamus, midbrain, pons, medulla, and cerebellum

Answer 20

Question 21

What does the frontal lobe control?

What does the parietal lobe control?

Answer 21

Frontal lobe: motor center, primary motor cortex, executive function

Parietal Lobe: sensory centor, primary somatosensory cortex

Question 22

Where is the primary visual cortex located within the brain?

Answer 22

Primary visual cortex is in the occipital lobe

Question 23

Where is the primary auditory cortex and the hippocampus located?

Answer 23

The temporal lobe is where the primary auditory cortex is located

Question 24

The _____ supports higher abstract brain functions

Like language, thought, action, conciousness, memory

Answer 24

The FOREBRAIN supports higher abstract brain functions

Like language, thought, action, consiousness, and memory

Question 25

Explain the flowchart with the brain, skeletal muscle and the ganglia

Answer 25

Question 26

Explain afferent vs efferent

Answer 26

Afferent is sensory (sensory inputs start in sensory neurons and then travel up to the brain) Efferent are signals that originate in the brain and travel down to motor neurons Think A before E

Question 27

Explain the connections within the CNS when it comes to the following: 1. Walking and chewing: motor activities, depend on sensory input and motor input from the ___ and the \_\_\_\_ 2. Gaze control: depend on connections between the \_\_\_, \_\_\_\_, and \_\_\_\_\_ 3. Homeostasis: blood pressure maintenance when rising from the sitting position: \_\_\_\_\_\_, \_\_\_\_\_, and \_\_\_\_

Answer 27

**Walking and chewing**: motor activities, depend on sensory input and motor output from the spinal cord and hindbrain **Gaze control**: depends on connections between midbrain, hindbrain, and cervical spinal cord **Homeostasis:** blood pressure maintenance when rising from sitting position: brainstem, spinal autonomic motor neurons

Question 28

The _____ contains circuits with the most distant connections to sensory inputs and motor outputs These circuits are involved in abstract functions such as memory, attention, and thought.

Answer 28

The FOREBRAIN contains circuits with the most distant connections to sensory inputs and outputs It is involved with abstract functions such as memory, attention, and thought

Question 29

Explain what the CNS vs the PNS comprises of Explain sensory vs motor divisions Then explain Autonomic vs Somatic

Answer 29

Question 30

What are the final common pathway for expression? The only way to access the 750 skeletal muscles in the body is via \_\_\_\_ Muscles cannot operate independently: ____ are essential for motor function

Answer 30

Motorneurons are the final common pathway for expression The only way to access the 750 skeletal muscles in the body is via motor neurons (MNs) Muscles cannot operate independently: MNs are essential for motor function (they do not work without CNS instructions, they cannot even hold tone in the absence of neural input)

Question 31

What controls the center that are critical for voluntary movement? What learns from motor experience to ensure accurate movement execution?

Answer 31

**Cortex and Brainstem** control centers critical to voluntary movement The **cerebellum** learns from motor experiences to ensure accurate movement execution

Question 32

What does the autonomic nervous system comprise of?

Answer 32

Autonomic nervous system comprises of the sympathetic, parasympathetic and enteric

Question 33

Explain how homeostasis is like a "smart feedback loop" within the human body

Answer 33

Smart feedback loop: Homeostasis circuits prevent out of range exursions BEFORE they happen Examples: pancreas releases insulin, glands release saliva in anticipation of eating Increase in blood pressure prior to standing up from supine position (forebrain pathway)

Question 34

The _________ chooses which movements occur Reflexes are controlled at the \_\_\_\_\_

Answer 34

The **Basal Ganglia** choose which movements occur Reflexes are controlled by the lowest level, at the **spinal cord**

Question 35

Explain the baroreceptor reflex: Where are the sensors? What does each one detect? Which cranial nerves are involved?

Answer 35

``` Baroreceptor Reflex: Catorid Sinus (detects BP increase and decrease) ``` Aortic Arch (BP increase only) Nerves IX (glossopharygal) and X (cranial)

Question 36

Explain the baroreceptor reflex when there is: an increase in BP a decrease in BP

Answer 36

Increase in BP: is detected by both the aortic arch and the carotid sinus... eventually decreases HR, decreases contracility and decreases vasoconstriction Decrease in BP: detected by carotid sinus... increases HR, increases contractility, and increases vasoconstriction Note, the signal goes to the medulla within the brain