Ch13/14 Exam 4 Parts 1-3 CNS

Question 1

Define the central nervous system

Answer 1

Includes brain and spinal cord, interpret sensory input and dictate motor output

Question 2

Describe the general pattern of the CNS and the (basic) difference between gray matter and white matter

Answer 2

The general pattern of the CNS is a central cavity, surrounded by gray matter, external to which is white matter. Gray matter is neuron cell bodies, white matter is myelinated (and some non-myelinated) fiber tracts (axons)

Question 3

Describe and identify the following structures of the brain:

Answer 3

Question 4

Cerebral hemispheres

Answer 4

This cerebral hammer for hemispheres are the two symmetrical halves of the brain divided by deep groove called the longitudinal fissure. Each hemisphere is responsible for different function.

Question 5

Diencephalon

Answer 5

The diencephalon forms essential core of the forebrain. It is surrounded by the cerebral hemisphere and encloses third ventricle. Thalamus, hypothalamus, epithalamus.

Question 6

Thalamus

Answer 6

The thalamus is the “gateway to cerebral cortex”
Sort, edits, processes, and relays ascending input
Meditates sensation, motor activities, cortical, arousal, learning, and memory

Question 7

Hypothalamus

Answer 7

Controls “ANS” (blood pressure rate/force of heartbeat, digestive, track, motility pupil size)
Initiates physical responses to emotions - perception of pleasure, fear, and rage and in biological rhythms and drives (ex. Sex drive)
Controls endocrine system
Produces posterior pituitary hormones and controls the secretions of anterior pituitary gland
In that role, it regulates body temperature, hunger, and satiety in response to nutrient blood levels or hormones, regulates water balance and thirst, sleep week cycles

Question 8

Epithalamus

Answer 8

The key structure of the epithalamus is the pineal gland (body) which secrets melatonin
Melatonin - helps regulate sleep week cycle; is secreted in response to decreased light

Question 9

Brain stem identify and describe key functions

Answer 9

The brain stem forms the base of the brain and is essentially an extension of the spinal cord.
There are three regions of the brainstem:
Midbrain
Pons
Medulla oblongata
Controls automatic behaviors necessary for survival
Position between the cerebrum and the spinal cord, it contains fiber tracts (white matter) connecting higher and lower neural centers, as well as nuclei (gray matter cell bodies) within the white matter

Question 10

Midbrain

Answer 10

Locate between the diencephalon and the pons
Involved in pain suppression
Participate in fight or flight response
Relay sounds from hearing receptors to sensory cortex

Question 11

Pons

Answer 11

Found between the midbrain and the medulla oblongata.
Primary compose of conduction tracts
- Connect higher brain centers and spinal cord
- Relay impulses between motor cortex and cerebellum
- Several cranial nerves issue from the pons
Nuclei within the pons, help maintain normal rhythm of breathing

Question 12

Oblongata

Answer 12

The medulla oblongata is the most inferior part of the brainstem. It blends into the spinal cord at its most inferior end.
The medulla plays a critical role as autonomic reflex center involved with maintaining body homeostasis. Contains three functional groups of visceral motor nuclei:
- Cardiovascular center - adjust force, and rate of heart contraction
- Vasomotor center - adjusts blood vessel diameter for blood pressure regulation
- Respiratory centers - generate respiratory rhythm, control rate and depth of breathing

Question 13

Cerebellum

Answer 13

Cerebellum receives input from the cortex brainstem and sensor receptors, it provides the timing and appropriate patterns of skeletal muscle contraction, which allows smooth coordinated movements

Question 14

Ventricles

Answer 14

The ventricles are set of four cavities in the brain where the cerebral spinal fluid (CSF) is produced.
The ventricles are connected to one another and into the central canal the spinal cord.
They are filled with cerebral spinal fluid, (CSF) and lined by ependymal cells.

Question 15

Describe and identify the location of the cerebral cortex, white matter and basil nuclei.

Answer 15

Cerebral cortex - is a rim of gray matter, found on the most superficial region of the cerebrum
White matter - is found internal to the cerebral cortex
Basil nuclei - gray matter (neuron cell bodies) found deep within white matter

Question 16

Define the key function of the cerebral cortex

Answer 16

The cerebral cortex is a site of our conscious mind. It is involved with awareness, sensory perception, voluntary motor, initiation, communication, memory, storage, and understanding.

Question 17

Define (in general terms) the three functional (motor sensory and multimodal areas of the cerebral cortex
What is their primary function? What type of activities do they control?

Answer 17

Motor (control of voluntary movement) ex. Control and planning of skeletal muscle movement understanding planning and directing spoken language, voluntary eye movements.

Sensory (conscious awareness of sensation) ex. Receives an integrate sensory information from skin skeletal muscle joints and tendons ;capable of identification of body region being stimulated; receives an interprets visual and auditory information. Conscious aware of balance perception of smell, taste, conscious awareness of visceral sensation.

Multimodal (integrate sensory information with motor responses) the multimodal areas receive inputs from multiple sensory areas and sent output to multiple areas. They allow us to give meaning to information story and memory tying to previous experience and deciding on actions. Appear to be the regions were sensations thoughts and emotions become conscious, makes us who we are.

Question 18

Describe what is meant by lateralization & cerebral dominance

Answer 18

The cerebral hemispheres are symmetrical and shape and size, but there is a lateralization between them. That is a division of labor between hemispheres the lateral hemisphere controls language, math, and logic the right hemisphere controls, visual, spatial skills, intuition, emotion, artistic and musical skills.
Cerebral dominance refers to the hemisphere that is dominant language. The left hemisphere is dominant in about 90% of people.
Despite lateralization the hemispheres communicate almost instantaneously via fiber tracts.

Question 19

Describe the cerebral white matter - what is it primarily composed of and what is its function?

Answer 19

Cerebral white matter consist primarily of myelinated fiber tracts (axons) It is responsible for communication between cerebral areas in between the cortex and lower CNS.

Question 20

What are the different types of fibers found in the cerebral white matter and what is the (general) job of these different fibers

Answer 20

Association fibers - horizontal, connect different parts of same hemisphere
Commissural fibers - horizontal, connect gray matter of two hemispheres
Projection fibers - vertical connect hemispheres with lower brain or spinal cord

Question 21

Describe the basal nuclei - what are they composed of? What is their (general) function?

Answer 21

The basil nuclear are groups of neurons cell bodies located deep within white matter of the cerebral cortex. They are functionally associated with nuclei in the diencephalon and midbrain. The basil nuclear receipt information from the entire cerebral cortex as well as other subcortical, nuclei and each other.

Functions include the modulation of movements or behaviors
- Influence muscle movements
- role in cognition and emotion
- regulate intensity of slow or stereotyped movements
- filter out incorrect/inappropriate responses
- inhibit antagonistic/unnecessary movements

Question 22

List the 4 structures that protect the brain

Answer 22

Bones of the skull
Meninges
Cerebrospinal fluid
Blood brain barrier

Question 23

Describe the function of the meninges and identify and describe each

Answer 23

Function of the Meninges
Cover and protect CNS tissue
Protect blood vessels and enclose venus sinuses
Contains cerebrospinal fluid
Form partitions in skull

From external to internal: Dura mater, arachnoid mater, pia mater

Question 24

Dura mater

Answer 24

The strongest meninx consist of two layers of fibrous connective tissue, which in places separate to form dural venus sinuses (collect Venus blood from brain and deliver it to the internal jugular veins of the neck). The more superficial layer is attached to the periosteum while the deeper layer forms the true external covering of the brain and continues caudally in the vertebral canal as the spinal durum mater.

Question 25

Arachnoid mater (including subarachnoid space and arachnoid villi)

Answer 25

The arachnoid matter is the middle layer with weblike extensions. It is separated from dura mater by the subdural space. Beneath the arachnoid matter is the subarachnoid space which contains CSF and the largest blood vessels of the brain. Spiderweb like extensions, span the space and the pia mater below arachnoid villi protrude into superior, sagittal sinus, and permit CSF reabsorption.

Question 26

Pia mater

Answer 26

Delicate vascularized connective tissue that clings tightly to the brain

Question 27

Describe the function and content of the cerebral spinal fluid (CSF) and where it is found

Answer 27

This cerebrospinal spinal fluid bathes the brain and spinal cord and forms a liquid cushion. It reduces the weight of the brain, protects the CNS from blows and other trauma and nourishes the brain and carries chemical signals from one part of brain to the other.

CNS is formed from blood plasma, but with less protein and different ion concentrations than plasma

It is found in the ventricles and subarachnoid space

Question 28

Describe what the blood brain barier is and (basically) how it works

Answer 28

The blood brain barrier prevents direct contact of the blood with neurons. It consists of multiple layers of defense
1. Continuous endothelium of capillary walls.
2. The thick basil laminate (extra cellular matrix) around capillaries
3. The feet of astrocytes which actually provide a signal to the endothelium for the formation of tight junctions. The tight junctions are the real blood-brain barrier. They are the tightest capillaries in the body.

Question 29

Spinal Cord - Identify and describe the basic anatomical structure

Answer 29

The spinal cord is to provide two-way communication to and from the brain

Question 30

Structures of the spinal cord in cross section

Answer 30

Question 31

Explain what is found in each gray matter horn of the spinal cord (cell bodies of motor neurons in ventral horn for example) and the dorsal root ganglia

Answer 31

Dorsal horns- are all cell bodies of interneurons that receive somatic and visceral sensory input

Ventral horns - cell bodies of somatic motor neurons

Lateral horns - only the thoracic and superior lumbar regions, sympathetic motor neurons serving visceral organs