Chapter 13 - 15 Study Guide
1. Structure and Function of Protection Around the Brain and Spinal Cord
- Cranial Protection:
- Skull: Protects the brain from physical damage.
- Meninges: Three layers of connective tissue that protect the brain and spinal cord.
- Dura Mater: Outermost, tough layer providing structural support.
- Arachnoid Mater: Middle layer with web-like fibers, contains the subarachnoid space where cerebrospinal fluid (CSF) circulates.
- Pia Mater: Innermost layer that closely adheres to the brain and spinal cord surface.
- Spinal Cord Protection:
- Vertebrae: Bony structure encasing the spinal cord.
- Epidural Space: Space between vertebrae and dura mater, contains fat and blood vessels for cushioning.
2. CSF Circulation
- CSF flows through the following:
1. Lateral ventricles →
2. Interventricular foramen →
3. Third ventricle →
4. Cerebral aqueduct →
5. Fourth ventricle →
6. Central canal of the spinal cord and subarachnoid space around the brain and spinal cord →
7. Absorbed into the bloodstream via arachnoid villi in the superior sagittal sinus.
3. Regions and Structures of Meninges, Brain, Spinal Cord, Spinal Nerve Plexuses, and Certain Spinal Nerves
- Meninges: Dura mater, arachnoid mater, pia mater.
- Brain Regions:
- Cerebrum: Hemispheres, lobes (frontal, parietal, occipital, temporal).
- Cerebellum: Coordinates movement and balance.
- Brainstem: Midbrain, pons, medulla oblongata—controls vital functions.
- Spinal Cord: Cervical, thoracic, lumbar, sacral regions.
- Spinal Nerve Plexuses:
- Cervical Plexus (C1-C4): Controls the diaphragm via the phrenic nerve.
- Brachial Plexus (C5-T1): Innervates the arms.
- Lumbar Plexus (L1-L4): Innervates the lower abdomen and legs.
- Sacral Plexus (L4-S4): Includes the sciatic nerve, which innervates the legs.
4. Principal Functions of Meninges, Brain, and Spinal Cord
- Meninges: Protect the CNS, anchor it to the skull and vertebral column, and allow for CSF circulation.
- Brain: Controls cognitive functions, motor activities, and homeostasis.
- Spinal Cord: Transmits signals between the brain and body, coordinates reflexes.
5. Differentiate Between Pyramidal and Purkinje Cells
- Pyramidal Cells: Found in the cerebral cortex, large triangular shape, responsible for motor control.
- Purkinje Cells: Located in the cerebellum, have extensive dendrites, involved in coordinating fine motor movements.
6. Limbic System and Reticular Formation
- Limbic System: Includes the amygdala, hippocampus, thalamus; involved in emotion, memory, and motivation.
- Reticular Formation: A network in the brainstem that regulates wakefulness, arousal, and sleep.
7. Blood-Brain Barrier
- Structure: A selective barrier formed by endothelial cells of capillaries in the brain, connected by tight junctions.
- Function: Protects the brain from harmful substances in the blood while allowing nutrients like glucose to pass through.
8. Cranial Nerves, Spinal Nerve Plexuses, and Selected Spinal Nerves
- Cranial Nerves:
1. Olfactory (I) - Smell.
2. Optic (II) - Vision.
3. Oculomotor (III) - Eye movement.
4. Trochlear (IV) - Eye movement.
5. Trigeminal (V) - Sensation from the face; chewing.
6. Abducens (VI) - Eye movement.
7. Facial (VII) - Facial expression, taste.
8. Vestibulocochlear (VIII) - Hearing, balance.
9. Glossopharyngeal (IX) - Taste, swallowing.
10. Vagus (X) - Heart, lungs, digestion.
11. Accessory (XI) - Head movement.
12. Hypoglossal (XII) - Tongue movement.
- Spinal Nerve Plexuses: Cervical, brachial, lumbar, sacral (see point 3).
9. Functional Areas of the Brain
- Frontal Lobe: Motor function, problem-solving, memory.
- Parietal Lobe: Sensory processing.
- Occipital Lobe: Vision.
- Temporal Lobe: Hearing, memory.
- Cerebellum: Balance, coordination.
- Broca’s Area: Speech production.
- Wernicke’s Area: Language comprehension.
10. Autonomic vs. Somatic Nervous System
- Autonomic Nervous System (ANS): Involuntary control, regulates heart rate, digestion, respiratory rate. Subdivided into:
- Sympathetic: "Fight or flight" responses.
- Parasympathetic: "Rest and digest" functions.
- Somatic Nervous System: Voluntary control of skeletal muscles.
11. Sympathetic Chain Ganglion
- Located alongside the spinal column, part of the sympathetic division of the ANS, involved in distributing sympathetic innervation to various organs.
12. Classification of Sensory Receptors
- By Location:
- Exteroceptors: Detect external stimuli (e.g., skin).
- Interoceptors: Detect internal body stimuli (e.g., organs).
- Proprioceptors: Detect position and movement (e.g., muscles, joints).
- By Stimulus Detected:
- Mechanoreceptors: Respond to touch, pressure, vibration.
- Thermoreceptors: Detect temperature changes.
- Nociceptors: Sense pain.
- Photoreceptors: Respond to light (eyes).
- Chemoreceptors: Detect chemicals (taste, smell).
- By Structure:
- Free nerve endings: Detect pain and temperature.
- Encapsulated receptors: Detect pressure and vibration.