Brain Anatomy Lab- Sheep

Question 1

Examination of Exterior of the brain

• Name:Connective tissue coverings
• Name:Most superficial
• Name:Intermediate
• Name:Deepest

Answer 1

Examination of Exterior of the brain

-meninges are three connective tissue coverings that encircle the brain and spinal cord.

-dura mater – most superficial; dense irregular
connective tissue; ntough. The dura mater, will
have been mostly removed when the brains were
prepared for the dissection; however, some of
the dura mater may remain near the base of the
brain.

-arachnoid – intermediate; fibrous connective
tissue consisting of collagen and elastic fibers;
avascular; this is still likely to cover your brain

-pia mater – deepest; thin transparent connective
tissue that adheres to the brain’s surface;
vascular; there are many blood vessels that
supply oxygen and nutrients to the brain. The
pia mater follows the gyri (ridges) and sulci
(grooves) and may be indistinguishable from the
brain.

Question 2

1- Structure

View of brain

Area of brain (not cerebellum or cerebrum)

Answer 2

1- Pons-lies directly superior to the medulla; it can be identified by the larger pair of bulges on the inferior surface

View of brain- Inferior

Area of brain- Brain Stem

Question 3

1- Structure

Part of brain

Answer 3

1- Left hemisphere

Part of brain- cerebellum (meaning “little brain”) on the inferior, posterior surface of the brain. The cerebellum participates in motor coordination. The cerebellum can be divided into two large hemispheres

Question 4

1- Structure

Part of the brain

Answer 4

1- Left hemisphere

Part of the brain- Cerebrum- largest region, composing over 2/3 of the brain. The cerebrum performs higher functions (intellect, reasoning, ect.) Like the cerebellum, the cerebrum can be divided into left and right hemispheres.

Question 5

1- Lobe

General locations of the five lobes of the cerebrum

Answer 5

1- Frontal

General locations of the five lobes of the cerebrum-The lobes roughly correspond in location to the cranial bones for which they are named. Their points of division are deep grooves; however, their boundaries are often vague.

Question 6

General locations of the three sulci of the brain

Between lobes 1 & 2

Between lobes 2 & 3

Between lobes 1, 2 & 4

Answer 6

General locations of the three sulci of the brain

Between lobes 1 & 2- Central sulcus - separates the frontal and parietal lobes.

Between lobes 2 & 3 -Parieto-occipital sulcus separates the parietal and occipital lobes; this division is extremely difficult to locate

Between lobes 1, 2 & 4- Lateral sulcus separates the temporal lobe from the frontal and parietal lobes. Note: the insula is the “hidden lobe. It cannot be seen from the surface of the brain because it lies within the lateral sulcus. Try to gently pull apart the lateral sulcus to reveal the insula.

Question 7

1- Structure and definition of group

Answer 7

1- optic nerve (cranial nerve II)

nerve – group of axons and/or dendrites in the peripheral nervous system (PNS)

tract – group of axons and/or dendrites in the central nervous system (CNS)

So, as the axons of the optic nerve enter the brain (CNS), the nerve becomes a tract.

Question 8

1- Structure

Answer 8

1- Optic Chiasm

Question 9

1- Structure

Answer 9

1- Cerebellum

Question 10

1- Structure(s)

Answer 10

1- Lateral Ventricles (there are 2)

Question 11

1- Structure

Answer 11

1- Lateral Ventricle- These are the largest of the brain’s four cerebrospinal fluid filled cavities; one is in each hemisphere. In a perfect mid-saggital section, the lateral ventricle will not be visible. Instead, it is just behind the septum pellucidum. The septum pellucidum is a thin partition between the left and right lateral ventricle. In essence, it is a wall of the lateral ventricle

Question 12

Structure at the point

Answer 12

Septum pellucidum is a thin partition between the left and right lateral ventricle. In essence, it is a wall of the lateral ventricle.

Question 13

1- Structure & name of specifications

Part of the brain

Answer 13

1- Tectum-the region of the midbrain that is posterior to the aqueduct. You may be able to appreciate that the tectum is comprised of 4 bumps (a pair superiorly, and a pair inferiorly). These bumps are called the superior colliculus and the inferior colliculus, respectively. The tectum participates in primitive automatic reflexes so that organisms can subconsciously escape potentially dangerous stimuli (i.e. startle reflexes).The superior colliculus receives visual information from the retina of the eye; the inferior colliculus receives information from the cochlea of the ear. The activity of the superior and inferior colliculi might cause us to instinctively look away from a bright flash of light or startle in response to a gunshot.

Part of the brain- Mesencephalon (midbrain)

Question 14

1- Structure

Answer 14

1- arbor vitae (tree of life) is named for its branching appearance. This white matter is believed to play an important role in sensory perception and motor output, i.e. it allows us to adjust our movements based on incoming sensory information = coordination.

Question 15

1- Structure

Area of the brain

Answer 15

1- The thalamus is most of the substance of the diencephalon – it looks very much like a ball. The thalamus is a key structure in relaying sensory information to the cerebral cortex (gray matter forming the outer layer of the cerebrum). It is often called the gateway to cortex; almost all sensory information passes through the thalamus before reaching the cortex.

Area of the brain- Diencephalon- just superior to the mesencephalon.

Question 16

1- Structure

Answer 16

1- The corpus callosum is a mass of axons (white matter) that connects the right and left hemispheres. This is one of the major commissural tracts (tracts crossing from one hemisphere to the other).