Bio 221: "Notes for Lab on the Brain"

Central Nervous System (CNS)

consists of the brain and spinal cord – it interprets incoming sensory information and issues instructions based on past experience. 

Peripheral Nervous System (PNS)

consists of the cranial and spinal nerves, ganglia and sensory receptors. Its function is to send information to and from the CNS.

Cerebral Hemispheres

Right and Left superior portions of the brain

Pia mater

the delicate innermost membrane enveloping the brain and spinal cord (the shiny covering)

Left Hemisphere of the brain is associated with __________ & ____________

1. language

2. speech

Right Hemisphere of the brain is associated with ____________ or ______________

abstract, conceptual or spatial processes

(skills associated with artistic or creative pursuits)

Cortex

outer portion of the brain made up of grey matter

Gyri

elevated ridges of tissue in the brain

Sulci

shallow grooves next to the Gyri

(They will contain blood vessels)

Fissures

deep grooves

Longitudinal Fissure

divides the brain into the right and left hemispheres

Central Sulcus

separates the frontal and parietal lobes as well as separating the motor functions from sensory functions

(The cortex is divided into functional areas)

Postcentral Gyrus

• located behind the central sulcus

• The function associated with this area is primary somatosensory. This is where sensory information will come from all over the body such as for pain, temperature and pressure.

• Immediately behind the primary area is the somatosensory association area in which the information gets interpreted. 

Precentral Gyrus

• located in front of the central sulcus.

• Primary Motor which is responsible for voluntary movement of skeletal muscle.

• A specialized motor speech area called Broca’s area is found at the base just above the lateral sulcus usually only on the left side.

• Damage to this area results in loss of speech. 

Prefrontal Cortex

the anterior portions of the frontal lobes; involved in intellect, complex reasoning and personality

Occipital Lobe

vision

Temporal Lobe

hearing

Olfactory Bulbs & Tracts

smell

Optic Nerve

vision

Optic Chiasma

where the medial optic fibers cross; It can be seen on the ventral surface of the brain and on the sagittal sections

Optic Tract

after the chiasma composed of medial fibers from the opposite eye and lateral fibers from the same side

Pituitary Gland

• will be missing from the brain unless the dura mater is present.

• When the dura mater is removed —> comes off.

• The structure that connects it to the brain is called the infundibulum.

• an endocrine gland that produces many different hormones.

Mammillary Body

relay station for olfaction

Cerebral Penduncles

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

Pons

• raised area just after the peduncles. means “bridge”

• consists primarily of motor and sensory fiber tracts connecting the brain with lower CNS centers.

Medulla Oblongata

• lowest brain stem region

• also composed of fiber tracts

• houses many vital autonomic centers involved in the control of heart rate, respiratory rhythm, and blood pressure as well as involuntary centers involved in vomiting and swallowing. 

Cerebellum

unconscious coordination of skeletal muscle activity and control of balance and equilibrium

Corpus Callosum

connects the right and the left hemispheres; forms the top of the lateral ventricles

Lateral Ventricle

space between the corpus callosum and the fornix 3 

Choroid

bundle of capillaries found in the ventricles. They are surrounded by epidemial cells and produce

CSF Fornix

bandlike fiber tract that makes the floor of the lateral ventricle; associated with olfaction and the limbic system (emotions)

Septum pellucidum

the membrane that separates the right and left lateral ventricle.

This will only be seen if the brain is cut just right and hasn’t been torn up with probes! The students don’t necessary have to identify this structure but should know what it is and does.

Third Ventricle

space surrounding the thalamus and below the fornix 

Thalamus

• Round structure below the fornix.

• It actually is a bi-lobed structure of gray matter that is connected by the intermediate mass.

• a major integrating and relay station for sensory impulses passing upward to the cortical sensory areas for localization and interpretation

Hypothalamus

• below the thalamus

• Important autonomic center involved in regulation of body temperature, water balance, fat and carbohydrate metabolism as well as sex drives, hunger and thirst

Pineal Body

• secretes melatonin which is a hormone associated with sleep and wake cycles.

• Depending on how the brain is cut it may or may not be present. 

Superior Colliculi

visual reflex center; Just below the pineal body

Inferior Colliculi

• auditory reflex center; below the superior colliculi

• If you pull the cerebellum down you can see what looks like “baby buns on a bicycle seat”. The baby buns are the superior colliculi and the bicycle seat is the inferior colliculi. In the crack of the buns is the pineal body.

Cerebral Aqueduct

slender canal just below the inferior colliculi. It connects the third and fourth ventricles. 

Arbor Vitae of the Cerebellum

• “Tree of Life”

• white matter within the cerebellum 

Meninges

cover and protect the brain and spinal cord

Dura Meter

outermost meninx; leathery 

Arachnoid mater

middle meninx; has arachnoid villi (spider web like – arachnids are spiders)

Pia Mater

delicate innermost layer next to the brain and spinal cord

Name the 6 Cranial Nerves and their functions

1. Olfactory – function smell (looks like rabbit ears)

2.  Optic - vision 

3. Oculomotor – eye movement; looks like flat fetticinni noodles and is on the peduncles

4. Trochlear – eye movement; thin round nerve still on the peduncle down low from the pons 

5. Trigeminal – chewing; in the brains without the dura mater it will be a stump lateral to the pons 

6. Abducens - eye movement; tiny round nerves on the surface of the medulla.

List the parts of the Spinal Cord

• Anterior Horn 

• Dorsal Horn 

• Ventral Root

• Dorsal Root

• Dorsal Root Ganglion 

• Spinal nerve 

• White Columns 

  • Posterior funiculus 

  • Anterior funiculus 

  • Lateral funiculus 

• Central canal 

• Gray Commissure