BIO 210 CHAPTER 13
The Central Nervous System
SUPPLEMENT 2
PowerPoint by John McGill
Supplemental Notes by
Beth Wyatt
CEREBELLUM
 Second Largest Division of the Brain
 Lies Below the Posterior Portion of the Cerebrum
CEREBELLUM
 Second Largest Division of the Brain
 Lies Below the Posterior Portion of the Cerebrum
CEREBELLUM: Transverse Fissure
OCCIPITAL
LOBE
CEREBELLUM
 Horizontal Groove that Separates the Cerebrum
from the Cerebellum
CEREBELLUM: CEREBELLAR
HEMISPHERES
 The 2 Halves of the Cerebellum that are Joined
CEREBELLUM: VERMIS
 The Central Portion of the Cerebellum
 Joins the 2 Cerebellar Hemispheres
Sheep Brain
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A- sagittal fissure
B - central sulcus
C - frontal lobe
D - parietal lobe
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E - occipital lobe
F - temporal lobe
G - cerebellum
H - vermis
I - medulla
CEREBELLUM: Convolutions
 Folds/ridges
CEREBELLUM: CONVOLUTIONS
CEREBELLUM: SULCI
 Grooves
CEREBELLUM: SULCI
CEREBELLUM: Gray & White Matter
 Arbor Vitae: Tree of Life
 Centrally Located White Matter of Cerebellum
ARBOR VITAE
http://www.vh.org/Providers/Textbooks/BrainAnatomy/Ch3Text/Section05.html
CEREBELLUM: Gray & White Matter
 Cerebellar Cortex
 Peripherally Located Gray Matter
Sheep Brain
 1. Arbor vitae (of
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cerebellum)
2. Corpus callosum
3. Fornix
4. Optic chiasma
5. Hypothalamus
6. Mammillary body
7. Lateral ventricle
8. Thalamus
9. Pineal body
10. Tectum
11. Cerebral aqueduct
12. Pons
13. Medulla oblongata
14. Spinal cord
15. Anterior commissure
16. Corpora quadrigemina
CEREBELLUM: Peduncles
 CEREBELLAR PEDUNCLES
 INFERIOR, MIDDLE, SUPERIOR
 Tracts that Connect Cerebellum to Other Parts of CNS (Primarily
to Brainstem)
Cerebellum Picture
FUNCTIONS of the CEREBELLUM
 All Functions of Cerebellum
Involve Skeletal Muscles
 SKILLED MOVEMENTS
 (WITH CEREBRAL CORTEX)
 Nerve Impulses from the
Cerebellum Added to Nerve
Impulses from the Cerebral
Cortex Produce Movements
(Skeletal Muscles) That are Coordinated and Precise
 EQUILIBRIUM
 Cerebellum Works with the Inner
Ear and Skeletal Muscles to Help
Maintain Balance
 POSTURE
 Cerebellum Controls Tonic
Contractions
DIENCEPHALON
 Between Brain
 3 MAJOR STRUCTURES
 THALAMUS
 HYPOTHALAMUS
 PINEAL BODY
DIENCEPHALON: THALAMUS
 Gray Matter Shaped Like a Dumb-bell Weight
DIENCEPHALON: HYPOTHALAMUS
 Gray Matter Below Thalamus
 Boundaries:
 Anterior Portion: Optic Chiasma
 Middle Portion: Infundibulum
 Posterior Portion: Mamillary Bodies
Sheep HYPOTHALAMUS (#9)
Optic Chiasma
Mammilary Body
Pituitary Gland
PINEAL BODY
 Pine-cone Shaped Structure Located Above the
Corpora Quadrigemina
Sheep Pineal
Functions of the Diencephalon
 THALAMUS
 SENSATIONS (TWO
PART MECHANISM)
 SERVES AS A MAJOR
RELAY STATION FOR
SENSORY IMPULSES
HEADED TO THE
CEREBRAL CORTEX
 PRODUCES CRUDE
AWARENESS OF
SOME GENERAL
SENSATIONS
Functions of the Diencephalon: Thalamus
 SENSATIONS: MAJOR RELAY STATION FOR SENSORY
IMPULSES HEADED TO THE CEREBRAL CORTEX
 Impulses That Will Eventually Reach the Cerebral Cortex and be
Interpreted as Sensations* are First Relayed Through the
Thalamus (Thalamus is the "Gateway to the Cerebral Cortex")
 * All Sensations Except for Possibly Olfactory
Functions of the Diencephalon: Thalamus
 PRODUCES CRUDE AWARENESS OF SOME
GENERAL SENSATIONS
 Crude Awareness: Not Precise/Fine Tuned
 Cerebral Cortex Interprets Sensations; However, the
Thalamus can Interpret Some General Sensations,
but Only on a Crude Level
Functions of the Diencephalon continued…
 ASSOCIATION OF SENSATIONS WITH EMOTIONS
 Thalamus Allows Us to Link Sensations (i.e., Taste) with Emotions (i.e.,
Unpleasantness)
 AROUSAL (ALERTING MECHANISM)
 Thalamus (as Well as Many Other Areas of the Brain) is Involved in
Keeping Us Awake and Alert (Consciousness)
 COMPLEX REFLEX MOVEMENTS
 The Thalamus is Involved in Some Reflexes
HYPOTHALAMUS
 REGULATES/CO-ORDINATES ANS
 There are Neuron Connections Between the Hypothalamus and the ANS
 LINKS "PSYCHE" AND "SOMA"
 Psyche: Mind/Awareness; Associated with the Cerebral Cortex
 Soma: Body/Effectors; Associated with the ANS and the Somatic NS
 Helps to Explain Psychosomatic Illness (Emotions can Lead to Changed
Body Functions)
HYPOTHALAMUS controls PITUITARY GLAND
 LINKS NERVOUS AND ENDOCRINE SYSTEMS
(CONTROLS PITUITARY GLAND)
 DIRECTLY: SYNTHESIZES POSTERIOR PITUITARY GLAND
HORMONES (WATER BALANCE)
 INDIRECTLY: REGULATES HORMONE SECRETION BY
ANTERIOR PITUITARY GLAND (RELEASING HORMONES)
HYPOTHALAMUS & Posterior Pituitary Gland
 DIRECTLY: SYNTHESIZES POSTERIOR PITUITARY
GLAND HORMONES (WATER BALANCE)
 The Hypothalamus Actually Builds the Hormones of the
PPG Just Stores and Releases Them
PPG;
HYPOTHALAMUS & Anterior Pituitary Gland
 INDIRECTLY: REGULATES
HORMONE SECRETION BY
ANTERIOR PITUITARY GLAND
(RELEASING HORMONES)
 The APG Builds Its Own Hormones;
However, Those Hormones Aren't
Released Until the Hypothalamus
"Says" They can be Released
 Mouse pituitary:
http://eulep.pdn.cam.ac.uk/Necropsy_of_
the_Mouse/index.php?file=Chapter_6.ht
ml#fig23
RELEASING HORMONE PATHWAYS
 The Way the Hypothalamus "Says" These Hormones can be
Released is Through Releasing Hormones
 i.e., Hypothalamus -----> Releasing Hormones -----> APG -----> Release
of APG Hormones
HYPOTHALAMUS: Overall Functions
 AROUSAL (ALERTING) MECHANISM
 REGULATES APPETITE AND FOOD INTAKE
 REGULATION OF BODY TEMPERATURE
HYPOTHALAMUS: Alertness
 AROUSAL (ALERTING) MECHANISM
 The Hypothalamus is Also Involved in This Mechanism
HYPOTHALAMUS: Appetite
 REGULATES APPETITE AND FOOD INTAKE
 The Hypothalamus Contains Both Appetite and Satiety
Centers (Clusters of Neurons)
 When the Appetite Center is Stimulated, One Feels
Hungry, When the Satiety is Stimulated, One Feels Full
HYPOTHALAMUS: Body Temperature
 REGULATION OF BODY TEMPERATURE
 The Hypothalamus Contains the Human Thermostat
PINEAL BODY
 REGULATES BIOLOGICAL CLOCK
 Individual's Unique Patterns of Eating and Sleeping;
 Also Includes Cycles That Occur in the Female Reproductive
System
 SECRETES HORMONES (MELATONIN)
 For This Reason, is Also Known as the Pineal Gland
 Secretes Melatonin