Exercise 17 - Mamm Phys Lab

Exam 1

Which underlined term is correct? The central nervous system/peripheral nervous system consists of the brain and spinal cord

Central nervous system

Which underlined term is correct? The most superior portion of the brain includes the cerebral hemispheres/brain stem

Cerebral hemispheres

True or False: Deep grooves within the cerebral hemispheres are known as gyri

False - deep grooves are known as fissures

On the ventral surface of the brain, you can observe the optic nerves and chiasma, the pituitary gland, and the mammillary bodies. These externally visible structures form the floor of the:

a. brain stem

b. diencephalon

c. frontal lobe

d. occipital lobe

Diencephalon

Which underlined term is correct? The inferior region of the brain stem, the medulla oblongata/cerebellum houses many vital autonomic centers involved in the control of heart rate, respiratory rhythm, and blood pressure

Medulla oblongata

Directly under the occipital lobe of the cerebrum is a large cauliflower-like structure known as the ________.

a. brain stem

b. cerebellum

c. diencephalon

Cerebellum

Which underlined term is correct? The outer cortex of the brain contains the cell bodies of cerebral neurons and is known as white matter/gray matter

Gray matter

The brain and spinal cord are covered and protected by three connective tissue layers called:

a. lobes

b. meninges

c. sulci

d. ventricles

Meninges

True or False: Cerebrospinal fluid is produced by the frontal lobe of the cerebrum and is unlike any other body fluid

False

How many pairs of cranial nerves are there?

Twelve

What is the central nervous system (CNS)?

Consists of the brain and spinal cord; primarily interpret incoming sensory information and issue instructions based on that info and past experiences

What is the peripheral nervous system (PNS)?

Consists of the cranial and spinal nerves, ganglia, and sensory receptors

What are the two subdivisions of the PNS?

Sensory portion and Motor portion

What is the sensory portion of the PNS?

Consists of nerve fibers that conduct impulses from sensory receptors toward the CNS

What is the motor portion of the PNS?

Contains nerve fibers that conduct impulses away from the CNS

What are the subdivisions of the motor portion?

Somatic division (voluntary system) and Autonomic division (ANS)

What is the somatic division (voluntary system) of the motor portion?

Controls the skeletal muscles

What is the autonomic nervous system (ANS) of the motor portion?

Controls smooth and cardiac muscles and glands

What is the neural tube?

The precursor to the CNS; simple tubelike structure that extends down the dorsal median plane

What are the three major regions of the brain?

Forebrain, midbrain, hindbrain

What are ventricles?

Chambers in four regions of the brain

What are the cerebral hemispheres?

Most superior portion of the brain

What are gyri?

elevated ridges of tissue

What are sulci?

Shallow grooves

What are fissures?

Deeper grooves

What is the longitudinal fissure?

Single deep fissure that separates the cerebral hemispheres

What does the central sulcus separate?

The frontal lobe from the parietal lobe

What does the lateral sulcus separate?

The temporal lobe from the parietal lobe

What does the parieto-occipital sulcus separate?

Divides the occipital lobe from the parietal lobe; on the medial surface of each hemisphere

What is the insula?

A fifth lobe of each cerebral hemisphere; buried deep within the lateral sulcus, covered by portions of the temporal, parietal, and frontal lobes

What is the composition and location of the cerebral cortex?

Outermost gray matter of the cerebrum

What is the cerebral white matter?

Composed of myelinated fibers bundled into tracts that carry impulses to/from the cortex

What is the diencephalon?

Part of the forebrain; includes the olfactory bulbs, optic chiasma, optic tracts, pituitary gland, and mammillary bodies

What are the structures of the brain stem?

Cerebral peduncles (midbrain), pons, medulla oblongata

What is the cerebral peduncles (midbrain)?

Fiber tracts in the midbrain connecting the pons below with the cerebrum above

What is the pons?

Consists of motor and sensory fiber tracts connecting the brain with lower CNS centers

What is the medulla onlongata?

Composed entirely of fiber tracts

What is the decussation of pyramids?

A crossover point for the major motor tracts descending from motor areas of cerebrum to spinal cord

What is the cerebellum?

Cauliflower-shaped; contains two major hemispheres and convoluted surface, as well as outer cortex made up of gray matter with inner region of white matter

What is the corpora quadrigemina?

Brain stem structure located on posterior aspect of midbrain

What are superior colliculi?

Visual reflex centers; two superior prominences

What are inferior colliculi?

Auditory reflex centers; two smaller inferior prominences

What is the corpus callosum?

Major commissure connecting cerebral hemispheres

What is the fornix?

Bandlike fiber tract concerned with olfaction and limbic system functions

What is the septum pellucidum

separates lateral ventricles of the cerebral hemispheres

What makes up the diencephalon?

The thalamus, hypothalamus, and epithalamus

What is the thalamus?

Two large lobes of gray matter that enclose narrow third ventricle of the brain

What is the interthalamic adhesion (intermediate mass)?

Connects the two thalamic lobes and bridges ventricle

What is the function of the thalamus?

Major integrating and relay station for sensory impulses passing upward to the cortical sensory areas for localization and interpretation

What is the hypothalamus?

makes up the floor and inferolateral walls of the third ventricle

What is the function of the hypothalamus?

Autonomic center involved in regulation of body temp, water balance, and fat/carbohydrate metabolism; involved with drives (hunger, thirst)

What is the function of the mammillary bodies?

Relay stations for olfaction

What is the epithalamus?

Forms roof of third ventricle; most dorsal portion of diencephalon

What are important structures of epithalamus?

Pineal gland (regulates sleep wake-cycle through melatonin) and choroid plexus (creates blood-CSF barrier)

What are meninges?

Connective tissue membranes that cover/protect brain and spinal cord

What is dura mater?

Outermost meninx; double-layered membrane.

What is periosteal layer?

inner layer of dura mater; attached to inner surface of skull forming periosteum

What is meningeal layer?

outer layer of dura mater; forms outermost brain covering, continuous with dura mater of spinal cord

What is falx cerebri?

Dips into longitudinal fissure to attach to crista galli of ethmoid bone of skull

What is the cavity created by falx cerebri?

Superior sagittal sinus; collects blood draining from brain tissue

What is falx cerebelli?

Separates cerebellar hemispheres

What is tentorium cerebelli?

Separates cerebrum from cerebellum below

What is the arachnoid mater?

Middle meninx; underlies dura mater

What is subdural space?

Partially separates dura mater from arachnoid mater

What is pia mater?

innermost meninx

What is meningitis?

inflammation of meninges

How is meningitis diagnosed?

taking sample of cerebrospinal fluid from subarachnoid space

How does the size of sheep cerebral hemispheres compare with those of humans?

The sheep’s cerebral hemispheres are smaller than those of the human

How does the size of sheep olfactory bulbs compare with those of humans?

The olfactory bulbs are larger in the sheep; the sense of smell is more important to sheep than humans for both protection and locating food

How does the depth of the fissures in the sheep’s cerebral hemispheres compare to that of the fissures in the human brain?

Sheep cerebral fissures are not as deep

What dural fold (falx cerebri or falx cerebelli) is missing in sheep that is present in humans?

Falx cerebelli

What is the function of the corpora quadrigemina?

Reflex centers for visual and auditory stimuli

How does the size of the fornix in the sheep brain compare with the size of the human fornix?

Larger in sheep’s brain compared to fornix of human brains. Sheep have more acute sense of smell than humans and rely on smell to alert them to danger, food sources, etc.

In which cerebral lobe is this region found? auditory cortex

temporal

In which cerebral lobe is this region found? primary motor cortex

frontal

In which cerebral lobe is this region found? primary sensory cortex

parietal

In which cerebral lobe is this region found? olfactory cortex

temporal

In which cerebral lobe is this region found? visual cortex

occipital

In which cerebral lobe is this region found? Broca’s area

frontal

Which options are not part of the brain stem?

Cerebral hemispheres, pons, midbrain, cerebellum, medulla, diencephalon

Cerebral hemispheres, cerebellum, diencephalon

A(n) ________ is an elevated ridge of cerebral tissue

gyrus

The convolutions seen in the cerebrum are important because they increase the ________

surface area

Gray matter is composed of ________

Neuron cell bodies

White matter is composed of ________

myelinated fibers

A fiber tract that provides for communication between different parts of the same cerebral hemisphere is called a(n) _________, whereas one that carries impulses FROM the cerebrum to lower CNS areas is called a(n) ________ tract

association tract; projection

The lentiform nucleus along with the caudate nuclei are collectively called the ________

Basal ganglia (corpus striatum)

Site of regulation of body temp and water balance; most important autonomic center

Hypothalamus

Consciousness depends on the function of this part of the brain

(small part of) cerebral hemisphere

Located in the midbrain; contains reflex centers for vision and audition

corpora quadrigemina

Responsible for regulation of posture and coordination of complex muscular movements

cerebellum

Important synapse site for afferent fibers traveling to the sensory cortex

thalamus

Contains autonomic centers regulating blood pressure, heart rate, and respiratory rhythm, as well as coughing, sneezing, and swallowing centers

medulla oblongata

large commissure connecting the cerebral hemispheres

corpus callosum

fiber tract involved with olfaction

fornix

connects third and fourth ventricles

cerebral aqueduct

encloses the third ventricle

thalamus

What is the embryonic origin of the diencephalon, including the thalamus, optic chiasma, and hypothalamus?

Forebrain

What is the embryonic origin of the medulla, pons, and cerebellum?

Hindbrain

What is the embryonic origin of the cerebral hemispheres?

Forebrain

What is the function of the basal ganglia?

Involved in regulation, modulation, and refinement of voluntary motor activity