Ap2 Final Study Guide - Chapter 14 Part 3

Front 1

The Cerebellum 1

Back 1

- Occupies the inferior and posterior aspects of the cranial cavity

- Has a highly folded surface that greatly increases the surface area of its outer gray matter cortex, allowing for a greater number of neurons

- Accounts for 1/10th of brain mass yet contains nearly 1/2 of the neurons in the brain

Front 2

The Cerebellum 2

Back 2

- Posterior to the medulla and pons and inferior to the posterior portion of the cerebrum

- A deep groove known as the transverse fissure, along with the tentorium cerebelli, which supports the posterior part of the cerebrum, separates the cerebellum from the cerebrum

Front 3

In superior or inferior views, the shape of the cerebellum resembles a butterfly. The central constricted area is _______

Back 3

- The vermis, and the lateral "wings" or lobes are the cerebellar hemispheres

- Each hemisphere consists of lobes separated by deep and distinct fissures

- The anterior lobe and posterior lobe govern subconscious aspects of skeletal muscle movements

- The flocculonodular lobe on the inferior surface contributes to equilibrium

Front 4

The superficial layer of the cerebellum, called the ______

Back 4

- Cerebellar cortex, consists of gray matter in a series of slender, parallel folds called folia

- Deep to the gray matter are tracts of white matter called arbor vitae that resemble branches of a tree

- Even deeper, w/in white matter, are cerebellar nuclei, regions of gray matter that give rise to axons carrying impulses from the cerebellum to other brain centers

Front 5

Three paired _______

Back 5

- Cerebellar peduncles attach the cerebellum to the brain stem

- These bundles of white matter consist of axons that conduct impulses between the cerebellum and other parts of the brain

Front 6

Superior and Middle Cerebellar Peduncles

Back 6

- Superior Cerebellar Peduncles -

• contain axons that extend from the cerebellum to the red nuclei of the midbrain and to several nuclei of the thalamus

- Middle Cerebellar Peduncles -

• the largest peduncles; their axons carry impulses for voluntary movements from the pontine nuclei into the cerebellum

Front 7

Inferior Cerebellar Peduncles Consist of :

Back 7

1. Axons of the spinocerebellar tracts that carry sensory info into the cerebellum

2. Axons from the vestibular apparatus of the inner ear and from the vestibular nuclei of the medulla and pons that carry sensory info into the cerebellum from proprioceptors in the head

Front 8

Inferior Cerebellar Peduncles Consist of :

Back 8

3. Axons from the inferior olivary nucleus of the medulla that enter the cerebellum and regulate the activity of cerebellar neurons

4. Axons that extend from the cerebellum to the vestibular nuclei of the medulla and pons

5. Axons that extend from the cerebellum to the reticular formation

Front 9

The Diencephalon

Back 9

- Forms a central core of brain tissue just superior to the midbrain

- Extends from the brain stem to the cerebrum and surrounds the third ventricle; it includes the thalamus, hypothalamus, and epithalamus

Front 10

Thalamus 1

Back 10

- 3 cm in length; makes up 80% of diencephalon

- Consists of paired oval masses of gray matter organized into nuclei w/ interspersed tracts of white matter

Front 11

Thalamus 2

Back 11

- A bridge of gray matter called the

intermediate mass (interthalamic adhesion) joins the right and left halves of the thalamus in about 70% of human brains

- A vertical y-shaped sheet of white matter called the internal medullary lamina divides the gray matter of the right and left sides of the thalamus

Front 12

Thalamus 3

Back 12

- The internal medullary lamina consists of myelinated axons that enter and leave the various thalamic nuclei

- Axons that connect the thalamus and cerebral cortex pass through the internal capsule, a thick band of white matter lateral to the thalamus

Front 13

The thalamus is the major relay station for most sensory impulses that reach the primary sensory areas of the cerebral cortex from the spinal cord and brain stem.

Back 13

- In addition, the thalamus contributes to motor functions by transmitting info from the cerebellum and basal nuclei to the primary motor area of the cerebral cortex

- The thalamus also relays nerve impulses between areas of the cerebrum and plays a role in the maintenance of consciousness

Front 14

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 14

1. The anterior nucleus receives input from the hypothalamus and sends output to the limbic system. It functions in emotions and memory

2. The medial nuclei receive input from the limbic system and basal nuclei and send output to the cerebral cortex. They function in emotions, learning, memory, and cognition

Front 15

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 15

3. Nuclei in the lateral group receive input from the limbic system, superior colliculi, and cerebral cortex and send output to the cerebral cortex. The lateral dorsal nucleus functions in the expression of emotions. The lateral posterior nucleus and pulvinar nucleus help integrate sensory information

Front 16

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 16

4. (Part One) - 5 nuclei are part of the ventral group. The ventral anterior nucleus receives input from the basal nuclei and sends output to motor areas of the cerebral cortex; it plays a role in movement control. The ventral lateral nucleus receives input from the cerebellum and basal nuclei and sends output to motor areas of the cerebral cortex; also plays a role in movement control.

Front 17

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 17

4. (Part Two) - The ventral posterior nucleus relays impulses for somatic sensations such as touch, itch, tickle, pain, and propioception from the face and body to the cerebral cortex. The lateral geniculate nucleus relays visual impulses for sight from the retina to the primary visual area of the cerebral cortex. The medial geniculate nucleus relays auditory impulses for hearing

Front 18

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 18

5. Intralaminar nuclei lie w/in the internal medullary lamina and make connections w/ the reticular formation, cerebellum, basal nuclei, and wide areas of the cerebral cortex. They function in arousal (activation of the cerebral cortex from the brain stem reticular formation) and integration of sensory and motor information

Front 19

Based of their positions and functions, there are 7 major groups of nuclei on each side of the thalamus :

Back 19

6. The midline nucleus forms a thin band adjacent to the third ventricle and has a presumed function in memory and olfaction

7. The reticular nucleus surrounds the lateral aspect of the thalamus, next to the internal capsule. This nucleus monitors, filters, and integrates activities of other thalamic nuclei

Front 20

Hypothalamus

Back 20

- A small part of the diencephalon located inferior to the thalamus

- It is composed of a dozen or so nuclei in four major regions:

• mammillary

• tuberal

• supraoptic

• preoptic

Front 21

Mammillary Region of the Hypothalamus

Back 21

- Adjacent to the midbrain; most posterior part of the hypothalamus

- Includes the mammillary bodies (2 small, rounded projections that serve as relay stations for reflexes related to the sense of smell) and posterior hypothalamic nuclei

Front 22

Tuberal Region of the Hypothalamus

Back 22

- The widest part of the hypothalamus; includes the dorsomedial nucleus, ventromedial nucleus, and arcuate nucleus, plus the stalklike infundibulum, which connects the pituitary gland to the hypothalamus

- The median eminence is a slightly raised region that encircles the infundibulum

Front 23

Supraoptic Region of the Hypothalamus

Back 23

- Lies superior to the optic chiasm (point of crossing of optic nerves) and contains the paraventricular nucleus, supraoptic nucleus, anterior hypo. nucleus, and suprachiasmatic nucleus

- Axons from the para. and supra. nuclei form the hypothalamohypophyseal tract, which extends through the infundibulum to the posterior lobe of the pituitary

Front 24

Preoptic Region of the Hypothalamus

Back 24

- Anterior to the supraoptic region

- Usually considered part of the hypothalamus b/c it participates w/ the hypo. in regulating certain autonomic activities

- This region contains the medial and lateral preoptic nuclei

Front 25

The hypothalamus controls many body activites and is one of the major regulators of homeostasis.

Back 25

- Sensory impulses related to both somatic and visceral senses arrive at the hypothalamus, as do impulses from receptors for vision, taste, and smell

- Other receptors w/in the hypo. itself continually monitor osmotic pressure, blood glucose level, certain hormone concentrations, and the temperature of blood