Practical 3 Study Guide - Lab 12

During a procedure called a lumbar puncture, CSF surrounding the meninges is withdrawn with a needle. Would you withdraw CSF if the needle were accidentally inserted into the epidural space instead of the subarachnoid space? Why or why not?

No CSF is present in the epidural space, which contains only fat. CSF is found only in the subarachnoid space.

Predict the effects of injuries to the following structures: pons

breathing impairment, inability to move (other than the eyes), disruption of consciousness

Which of the following spaces around the spinal cord is filled with cerebrospinal fluid(CSF)? a. epidural space b. subdural space c. subarachnoid space d. all of the above

c. subarachnoid space

What are the four main regions of the brain?

1. cerebrum 2. diencephalon 3. brainstem 4. cerebellum

The spinal cord extends from the ______ of the occipital bone to the _____ vertebra. It terminates as the _____ and gives off a bundle of nerve roots called the _____.

1. foramen magnum 2. L1 and L2 3. conus medullaris 4. cauda equina

During a procedure called a lumbar puncture, CSF surrounding the meninges is withdrawn with a needle. Often, the sampled CSF is tested for bacteria or viruses if a brain infection is suspected. Why would CSF sampled from the spinal cord give you information about the condition of the brain?

CSF in the spinal cord is continuous with that of the brain; therefore, viruses/bacteria in the fluid surrounding the brain will also be in the fluid surrounding the spinal cord.

During a procedure called a lumbar puncture, CSF surrounding the meninges is withdrawn with a needle. This procedure generally is performed between L3 and L5. Why do you think the fluid id withdrawn here rather than from higher up in the vertebral column?

CSF is withdrawn here to avoid injuring the spinal cord, which ends at L1-L2.

A common way to deliver anesthesia for surgery and childbirth is to inject the anesthetic agent into the epidural space(epidural anesthesia). Why do you think the anesthetic is injected into the epidural space instead of the subarachnoid space?

Injecting into the subarachnoid space puts the needle right next to the spinal cord and makes it easier to accidentally injure it. Injecting into the epidural space doesn't require inserting the needle next to the spinal cord, nor does it require piercing any of the meninges, so it is a safer procedure.

Predict what might happen if the choroid plexuses produced excessive CSF, in amounts greater than the dural venous sinuses were able to absorb.

The accumulation of CSF would put pressure on the brain. This leads to a variety of symptoms including headache, vision changes, mental changes, and motor impairment.

An individual sustains injuries to only the ascending tracts of the spinal cord. Will this person experience deficits in movement, sensation, both, or neither? Explain.

The ascending tracts are the sensory tracts that carry sensory stimuli from the PNS to the CNS. Damage to these tracts will prevent sensory stimuli from being delivered to the CNS from the PNS, and the individual will therefore experience deficits in sensory perception.

Agenesis of the corpus callosum is a rare birth defect characterized by a lack of development of the corpus callosum. What sort of functional impairment would you expect from such a defect? Explain.

The corpus callosum connects the right and left cerebral hemispheres, enabling them to communicate. If the corpus callosum doesn't develop, the two hemispheres will be unable to communicate, leading to symptoms such as poor motor coordination and cognitive deficits.

Gray matter consists of a. cell bodies, dendrites and unmyelinated cells b. myelinated cells c. unmeylinated axons d. myelinated cell bodies, dendrites and axons

a. cell bodies, dendrites, and unmyelinated cells

Cerebrospinal fluid is produced by the a. ventricles of the brain. b. arachnoid granulations. c. dural sinuses. d. choroid plexuses.

d. choroid plexuses

T/F The diencephalon consists of the midbrain, pons and medulla oblongata.

false; brainstem

T/F The cerebral cortex is the outer 2 mm of white mater of the cerebrum.

false; gray matter

Predict the effects of injuries to the following structures: cerebellum

problems coordinating ongoing movement, difficulty learning new motor skills, problems with fine motor control

Predict the effects of injuries to the following structures: thalamus

problems with sensory perception, movement disorders, sleep-wake cycle dysfunction

T/F The cerebellum monitors ongoing movement to reduce motor error.

true

T/F The corpus callosum is a large tract of white matter that connects the right and left cerebral hemispheres.

true

T/F The outer, tough meninx around the brain is the dura mater.

true