13-1 nervous system ii: brain lecture 13. 13-2 brain major parts of the brain –brainstem...
TRANSCRIPT
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Nervous System II: BrainLecture 13
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Brain
Major parts of the brain– Brainstem
– Cerebellum
– Diencephalon
– Cerebrum
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Brainstem
• Connects spinal cord to brain• Parts
– Medulla oblongata– Pons– Mesencephalon
Fig. 15.1
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Brainstem• Medulla oblongata or medulla
– Regulates: Heart rate, blood vessel diameter, respiration, swallowing, vomiting, hiccupping, coughing, and sneezing
• Pons– Sleep and respiratory center
• Mesencephalon– Integral part of auditory
pathways in CNS
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Cerebellum• Involved in control of:
balance, posture, locomotion, and fine motor coordination producing smooth flowing movements
Fig. 15.22
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Diencephalon
• Components– Thalamus, Epithalamus, Hypothalamus
Fig. 15.15
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Diencephalon
• Thalamus– Largest part of
diencephalon
– Most sensory input projects to here
– Influences mood and actions as fear or rage
• Epithalamus– Pineal gland may
influence sleep-wake cycle
• Hypothalamus– Functions
• ANS control
• Endocrine control
• Muscle control
• Temperature regulation
• Regulation of food and water intake
• Emotions
• Regulation of sleep-wake cycle
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Cerebrum• Largest portion of brain• Hemispheres
– Right – Left– Lobes: frontal, parietal,
occipital, temporal, insula
• Gyrus• Sulcus
Fig. 15.10
Fig. 15.1
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Meninges• Connective tissue
membranes– Dura mater:
Superficial– Arachnoid mater– Pia mater:
Bound tightly to brain
– Spaces • Subdural:
Serous fluid• Subarachnoid:
Cerebrospinal fluid (CSF)
Fig. 15.4
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Ventricles
• Ventricles: Lateral ventricles (2), third ventricle, fourth ventricle
• Choroid plexuses produce CSF which fills ventricles and other parts of brain and spinal cord
Fig. 15.6
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Cerebrospinal Fluid (CSF)
• Similar to serum with most of proteins removed
• Bathes brain and spinal cord• Provides a protective cushion around CNS• Provides some nutrients to CNS tissues• Produced by ependymal cells in the
ventricles of the brain
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Brain Blood Supply• Brain
– Requires tremendous amount of blood– Receives 15-20% of blood pumped by heart– Interruption can cause unconsciousness and
irreversible brain damage– High metabolic rate and dependence on
constant supply of oxygen and glucose– Receives blood through arteries
• Internal carotid arteries (carotid canal) and vertebral arteries (foramen magnum)
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Review Question
The primary link between the nervous system and the endocrine system (consists of glands that secrete hormones) is the
(a) Hypothalamus
(b) Pons
(c) Medulla oblongata
(d) Cerebellum
(e) Midbrain
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Points to Remember• Major parts of brain are: brain stem, cerebellum,
diencephalon and cerebrum.• Injury to medulla oblongata often fatal since it
contains vital parts for control of breathing, heart rate and blood pressure.
• Cerebellum provides important control of skeletal muscles for coordination of movement and posture.
• Diencephalon functions in several emotions and control of sleep-wake cycle.
• Cerebrum is largest part of brain with functions in emotions, higher level thinking, interpretation of sensory data and muscular control.
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Questions?