1. The Brain and Cranial Nerves
Chapter 14
The Brain and Cranial Nerves

3. Brain and Cranial Nerves

4. Brain and Cranial Nerves
Part of CNS contained in cranial cavity
Control center for many of body’s functions
Much like a complex computer but more
Parts of the brain
Brainstem
Cerebellum
Diencephalon
Cerebrum
Cranial nerves
Part of PNS arise directly from brain

5. Brainstem Connects spinal cord to brain Parts Medulla oblongata Pons
Midbrain

6. Brainstem Medulla oblongata or medulla Pons Midbrain
Regulates: Heart rate, blood vessel diameter, respiration, swallowing, vomiting, hiccupping, coughing, and sneezing
Pyramids: Decussate
Pons
Sleep and respiratory center
Midbrain
Integral part of auditory pathways in CNS

7. Brainstem and Diencephalon

8. Cerebellum
Involved in control of: balance, posture, locomotion, and fine motor coordination producing smooth flowing movements

9. Diencephalon Components
Thalamus, Subthalamus, Epithalamus, Hypothalamus

10. Diencephalon Hypothalamus Thalamus Functions Subthalamus Epithalamus
Largest part of diencephalon
Most sensory input projects to here
Influences mood and actions as fear or rage
Subthalamus
Involved in controlling motor functions
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

11. Cerebrum Largest portion of brain Divisions Cortex: Outer surface
Right
Left
Lobes: Frontal, parietal, occipital, temporal, insula
Cortex: Outer surface
Medulla: Center

12. Basal Nuclei and Limbic System
Motor function control
Limbic system
Basic survival functions as memory, reproduction, nutrition
Emotions

13. Limbic System

14. Meninges Connective tissue membranes Dura mater: Superficial
Arachnoid mater
Pia mater: Bound tightly to brain
Spaces
Subdural: Serous fluid
Subarachnoid: CSF

15. Ventricles
Ventricles: Lateral ventricles (2), third ventricle, fourth ventricle
Choroid plexuses produce CSF which fills ventricles and other parts of brain and spinal cord
Blood-cerebrospinal fluid barrier: Substances do not pass between cells but through due to tight junctions of blood endothelial cells

16. 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

17. Flow of CSF

18. Brain Blood Supply Brain Blood-Brain barrier
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
Blood-Brain barrier
Capillary endothelial cells along with astrocytes and basement membrane
To be considered when developing drugs

19. Formation of the Neural Tube

20. Development of Brain Segments and Ventricles

21. Cranial Nerves
Indicated by Roman numerals I-XII from anterior to posterior
May have one or more of 3 functions
Sensory (special or general)
Somatic motor (skeletal muscles)
Parasympathetic (regulation of glands, smooth muscles, cardiac muscle)

22. Cranial Nerves Olfactory (I) Optic (II) Oculomotor (III)
Trochlear (IV)
Trigeminal (V)
Abducens (VI)
Facial (VII)
Vestibulocochlear (VIII)
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
Hypoglossal (XII)