Central nervous system

• CNS

• Brain -divisions– Hypothalamus– Medulla oblongata– Cerebellum

Suprachiasmatic nucleus in hypothalamus is major circadian clock of mammals

Figure 10.4 Nervous systems of different phyla (Part 1)

Figure 10.4 Nervous systems of different phyla (Part 2)

Figure 10.6 The organization of a vertebrate central nervous system

The central nervous system

• Begins as a hollow tuve

• Embryonic development- 5 regions• Telencephalon• Diencephalon• Mesencephalon• Metencephalon• myelencephalon

Figure 10.8 A schematic of vertebrate brain structure

Evolution of the vertebrate brain

Figure 10.9 Localization of function in the mammalian brain: old and current views (Part 1)

Cerebrum

• 2 hemispheres– Outer gray matter– Inner white matter

• Specialization of functions• Left hemisphere

– Dominant in language and analytical ability

• Right hemisphere– Pattern recognition,

• Communication between hemisphere– Corpus callosum

Figure 10.9 Localization of function in the mammalian brain: old and current views (Part 2)

Cerebral Lateralization

• Cerebral dominance:– Specialization of one

hemisphere.

• Left hemisphere: – More adept in language

and analytical abilities.– Damage:

• Severe speech problems.

• Right hemisphere: – Most adept at visuospatial

tasks.– Damage:

• Difficulty finding way around house.

Figure 10.10 Functional neuroimaging demonstrates localization of function in cerebral cortex

Figure 10.11 Maps in the human brain (Part 1)

Figure 10.11 Maps in the human brain (Part 2)

Homeostatic role of hypothalamus

• Autonomic control center• Center for emotional response and behavior• Body temperature regulation• Regulation of food intake- satiety and hunger

center• Regulation of water balance and thirst • Regulation of sleep-wake cycle• Control of endocrine systems

Pituitary Gland

• Posterior pituitary:– Stores and releases ADH (vasopressin) and

oxytocin.

• Hypothalamus produces releasing and inhibiting hormones that are transported to anterior pituitary.– Regulate secretions of anterior hormones.

• Anterior pituitary:– Regulates secretion of hormones of other endocrine

glands.

Role of medulla oblongata – maintain homeostasis

• Cardiac and vasomotor center– Adjust force and rate of heart contraction– Regulate blood pressure by acting on smooth

muscle of blood vessels

• Respiratory center– Control rate and depth of breathing

• Other regulatory activities– Vomiting, hiccupping, swallowing, coughing,

sneezing ….. etc

Role of cerebellum

• Process inputs received from the motor cortex, brain stem nuclei, and sensory receptors

• Provide precise timing and appropriate patterns of skeletal muscle contraction

• Needed for smooth coordinated movements

• Needed for equilibrium

Figure 10.17 Suprachiasmatic nucleus in hypothalamus is major circadian clock of mammals (Part 1)

Figure 10.14 Daily rhythm of several physiological functions in a human

Figure 10.15 Circadian rhythm of metabolic rate and motor activity for a chaffinch (Part 1)

Figure 10.15 Circadian rhythm of metabolic rate and motor activity for a chaffinch (Part 2)

Figure 10.16 Activity rhythms of two nocturnal flying squirrels (Glaucomys volans)

Figure 10.17 Suprachiasmatic nucleus in hypothalamus is major circadian clock of mammals (Part 2)