Lab 11 Nervous System I: Nervous Tissue and the Spinal Cord PDF

11-6 **LAB 11 NERVOUS SYSTEM I: NERVOUS TISSUE AND THE SPINAL CORD** 1. Understand the structure and function of the central and peripheral nervous systems. 2. Describe the structure and function of neurons. 3. List six types of neuroglial cells and describe the basic function of each...

11-6 **LAB 11 NERVOUS SYSTEM I: NERVOUS TISSUE AND THE SPINAL CORD** 1. Understand the structure and function of the central and peripheral nervous systems. 2. Describe the structure and function of neurons. 3. List six types of neuroglial cells and describe the basic function of each. 4. Identify neuron structures and describe their functions. 5. Identify important structures of the spinal cord. 6. Learn the components of and understand the function of a reflex arc. 7. Perform simple tests to demonstrate various reflexes. I. **THE NERVOUS SYSTEM** II. **STRUCTURE OF NERVOUS TISSUE** PART A: NEURONS =============== 1. **Sensory (afferent) neurons**: the neuron that conducts the impulse from the sensory receptor to the central nervous system. 2. **Interneuron (association neuron)**: integrates information from the sensory neurons and passes the stimulus to motor neurons. 3. **Motor (efferent) neurons**: the neuron that conducts the impulse from the central nervous system to an effector, usually a muscle or a gland. +-----------------------------------+-----------------------------------+ | STRUCTURE | FUNCTION AND DESCRIPTION | +===================================+===================================+ | dendrites | Receive signals | | | (neurotransmitters) from other | | | neurons and send the info to cell | | | body/ tree-like branches from | | | main part of neuron | +-----------------------------------+-----------------------------------+ | cell body | Integrates info and controls the | | | neuron activities/ central part | | | of neuron, containing the nucleus | +-----------------------------------+-----------------------------------+ | axon: | Determines if an electrical | | | signal is strong enough to send | | bulbs/ varicosities | an action potential down the | | | axon/ small region at the | | | beginning of the axon, where the | | | axon connects to the cell body | +-----------------------------------+-----------------------------------+ | | Allows neuron to communicate with | | | multiple other neurons/ branches | | | off main axon | +-----------------------------------+-----------------------------------+ | | Releases neurotransmitters | | | (chemical signals) to pass the | | | signal to other neurons/ the | | | small branches at the end of the | | | axon | +-----------------------------------+-----------------------------------+ | | Contains and releases | | | neurotransmitters to pass signals | | | axons synapse (gap between | | | neurons) / small bulb-like | | | structures at the end of the axon | | | terminal | +-----------------------------------+-----------------------------------+ | Schwann cells | Produce myelin, which helps spend | | | up nerve signals transmission / | | | cells that wrap around the axon | | | in the PNS | +-----------------------------------+-----------------------------------+ | | Insulates the axon, speeding up | | | the transmission of electric | | | signals/ A fatty covering around | | | the axon, formed by Schwann cells | | | or oligodendrocytes | +-----------------------------------+-----------------------------------+ | | Helps in regeneration of damage | | | nerve fibers in the PNS/ the | | | outer layer of the Schwann cells | | | that surround the myelin sheath | +-----------------------------------+-----------------------------------+ | myelin sheath gaps/ nodes of | Allow the electrical signals to | | Ranvier | jump from one node to the next, | | | speeding up transmission of the | | | action potential/ small gaps | | | between the myelin sheaths along | | | the axon | +-----------------------------------+-----------------------------------+ 1. **Multipolar neurons** have several dendrites and one axon and are the neuron type that dominates the CNS. 2. **Bipolar neurons** have one dendrite and one axon and are found in the retina of the eye, inner ear, and the nasal epithelium. 3. **Unipolar neurons** have a fused axon and dendrite that emerge from the cell body as one unit. The dendrites of these neurons form many of the other sensory receptors in the PNS. PART B: NEUROGLIA ================= D:\\Users\\sconnors\\AppData\\Local\\Microsoft\\Windows\\Temporary Internet Files\\Content.Word\\pap14\_fig\_12\_06.jpg/myelin sheath gap GLIAL CELL FUNCTION AND DESCRIPTION ------------------ ----- --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- astrocytes CNS Supports neurons in the CNS by maintaining the chemical environment of calcium and potassium/ star shaped cell in the CNS most abundent oligodendrocytes CNS Produces myelin in CNS/ cells with a few branches that wrap around axons in the CNS microglia CNS Phagocytize pathogens, dead cells, or debris/ small mobile cells ependymal cells CNS Help produce and circulate cerebrospinal fluid (CSF)/ ciliated cells that help move CSF through the CNS Schwann cells PNS Produce myelin in PNS/ cells that wrap around axons satellite cells PNS Surround neurons cell bodies in ganglia and regulate the environment around neurons/ small flattered cells that provide structural support and regulate nutrients, and waste in PNS ganglia PART A: THE MENINGES ==================== -------------------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- dura mater Protects spinal cord/ Made of dense irregular tissue connective, outermost and the toughest layer of the meninges arachnoid mater Provides a cushion and maintaining integrity of the CNS/ Web-like structure made of collagen and elastic fibers middle layer of the meninges pia mater Directly in contact with the spinal cord and brain, helping supply nutrients and remove waste with blood vessels/ Inner most layer of the meninges thin and delicate with blood vessels epidural space Serves as a cushion and a passageway for blood vessels and fat to protect spinal cord/ space between the dura mater and inside of the vertebral column subdural space Contains small amount of fluid to reduce friction and cushioning/ narrow space located between dura mater and arachnoid mater contains interstitial fluid subarachnoid space Space filled with CSF which helps cushion the spinal cord, provide nutrients, and remove waste/ between arachnoid mater and pia mater -------------------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- PART B: THE SPINAL CORD ======================= +-----------------------------------+-----------------------------------+ | STRUCTURE | FUNCTION AND DESCRIPTION | +===================================+===================================+ | gray matter anterior horn | Contains cell bodies of neurons | | posterior horn | involved in processing and | | | integrating info has unmyelinated | | | axons | | | | | | Contains motor neurons that | | | signals skeletal muscles for | | | voluntary movement/ butterfly | | | shape anterior part of grey | | | matter | | | | | | Contains sensory neurons that | | | receive input from sensory | | | receptors/ butterfly shape | | | posterior part of grey matter | +-----------------------------------+-----------------------------------+ | white matter | Contains myelinated axons and is | | | responsible for transmitting | | | signals up and down the spine | | | forms motor and sensory pathways/ | | | surrounds grey matter outer layer | | | in spinal cord | +-----------------------------------+-----------------------------------+ | spinal nerves | Transmits sensory and motor info | | | between spinal cord and the body/ | | | exit through openings between | | | vertebrae at each lateral exit | +-----------------------------------+-----------------------------------+ | central canal | Small fluid filled space that | | | runs the length of the spinal | | | cord and contains CSF/ narrow | | | central tube located at the very | | | center of the grey matter | +-----------------------------------+-----------------------------------+ | nerve roots anterior root | Bundles of nerve fibers that exit | | posterior root ganglia | from the spinal cord before | | | forming spinal nerves | | | | | | Contains motor neurons that carry | | | signals from the spinal cord to | | | muscles and glands/ anterior | | | region connected to posterior | | | horn | | | | | | Contains sensory neurons that | | | carry sensory info from the body | | | to the spinal cord/ posterior | | | region connected to posterior | | | horn | | | | | | Clusters of neurons cell bodies | | | found outside the CNS/ just | | | outside the spinal cord, located | | | posterior root before joining to | | | form spinal nerves | +-----------------------------------+-----------------------------------+ | anterior median fissure | Groove that divides spinal cord | | | into left and right halves/ in | | | the front midline of the spinal | | | cord | +-----------------------------------+-----------------------------------+ | posterior median sulcus | Shallow groove that divides the | | | spinal cord into left and right | | | halves/ along the posterior | | | midline of spinal cord | +-----------------------------------+-----------------------------------+ | filum terminale | Strand of connective tissue that | | | anchors the spinal cord to | | | coccyx/ thin fibrous extension of | | | the pia mater | +-----------------------------------+-----------------------------------+ **Figure 11.4 Spinal cord in vertebra.** From Tortora and Derrickson, Principles of Anatomy and Physiology, PART C: HISTOLOGY OF THE SPINAL CORD ==================================== *What type of vertebrae is shown on the slide above? Describe the features that allow you to determine the vertebrae type.* PART D: SPINAL NERVES AND PLEXUSES ================================== Find these structures on the reflex arc model, and label Figure 11.6. -- --------------------------------------------------------------------------------------------------------- ------------------------------------------------------------- A simple neural pathway that controls a reflex action/ allows for rapid response to protect from danger \-\-\-\-- A fast involuntary movement in response to stimuli/ can generate response without brain Pulling hand away from hot stove Detect stimuli Heat receptors in skin to detect hot stove Transports signal from receptor to CNS Sends signal to spinal cord Processes info and sends signal to motor neuron to carry a response/ found in CNS Processes info and sends a response Transports signals from integrating center to effector Receives electric signal and transports signal to effectors The organ that responds to the motor neuron's signal/ muscle contraction or gland secretion Muscles of the arm contract to move away -- --------------------------------------------------------------------------------------------------------- ------------------------------------------------------------- PART A: PERFORMING BASIC REFLEX TESTS ===================================== Procedure 1: Achilles Tendon Reflex ----------------------------------- 1. One partner (the subject) should stand resting one knee on a lab stool, allowing their foot to hang relaxed. 2. The other partner (the tester) should locate the Achilles tendon on the back of the ankle, and using the long side of a rubber mallet, softly strike the Achilles tendon. 3. Observe any movement of the foot. 4. Change partners and repeat. Record your results in Table 11.1. Procedure 2: Patellar Reflex ---------------------------- 1. The subject should sit on the lab bench with both legs hanging freely. 2. The tester should locate the patellar tendon (slightly inferior to the patella). Softly strike the patellar tendon with the wide end of the rubber mallet. 3. Observe any movement of the leg. 4. Change partners and repeat. Record your results in Table 11.1. Procedure 3: Biceps Reflex -------------------------- 1. Facing each other, the tester should hold the subject's left elbow in their right hand. The subject's forearm should rest on the tester's forearm, so the subject's arm is bent and relaxed. 2. The tester then places their thumb on the biceps tendon found in the antecubital region. 3. The tester should then strike the tip of their thumb with the mallet. 4. Watch for movement of the subject's brachium, antebrachium, hand or fingers. 5. Change partners and repeat. Record your results in Table 11.1. Procedure 4: Triceps Reflex --------------------------- 1. The subject should flex their arm at the elbow. 2. The tester should hold the subject's wrist and the subject should relax their arm completely, resting the weight of their arm in the tester's fingers. 3. The tester should then strike the triceps tendon, just above the olecranon of the ulna. 4. Observe any movement in the arm. 5. Change partners and repeat. Record your results in Table 11.1. Procedure 5: Plantar Flexion Reflex ----------------------------------- 1. The subject should remove their right shoe and sock. 2. The tester should then take the blunt end of a pencil (or the metal handle from the mallet) and run it firmly from the heel, along the outer edge of the sole of the foot and across the ball of the foot towards the big toe. 3. Observe any movement in the toes. 4. Change partners and repeat. Record your results in Table 11.1. Procedure 6: Salivary Reflex Demonstration - view side bench ------------------------------------------------------------ 1. The subject should rinse their mouth with the drinking water provided. 2. The tester should dip a cotton swab in water and place it under the subject's tongue for a few seconds. Dispose of the swab by placing it back in its paper package and putting it in the garbage. 3. The subject should then collect all saliva produced for three minutes in a clean graduated cylinder. Measure the volume produced (not including the bubbles) and record in Table 11.1. Dispose of the saliva in the sink and rinse the graduated cylinder. Volume of saliva produced with swab dipped in water: 4. The subject should then rinse their mouth with water. 5. The tester should then dip a new cotton swab in the glucose solution and place it under the subject's tongue. Dispose of the cotton swab as indicated above. 6. The subject should then collect all saliva produced for three minutes in a clean graduated cylinder. Measure the volume produced (not including the bubbles) and record in Table 11.1. Dispose of the saliva in the sink and rinse the graduated cylinder. Volume of saliva produced with swab dipped in glucose: [ ] 7. The subject should rinse their mouth with water again. 8. Repeat steps 5 -- 7 with the lemon juice. Volume of saliva produced with swab dipped in lemon juice: 9. Wash the graduated cylinder with soap and the test tube brush after each subject. 10. Change partners and repeat. Record your results in Table 11.1. Procedure 7: Pupillary Light Reflex ----------------------------------- 1. The subject should stand facing the tester. The tester should note the relative size of the subject's pupils. 2. The tester should quickly flash a penlight into the eye of the subject and note any change in pupil diameter. 3. Change partners and repeat. Record your results in Table 11.1. Procedure 8: Diving Reflex Demonstration - view data on side bench ------------------------------------------------------------------ 1. Obtain a pulse oximeter from your instructor. Choose one member of your group to be the subject and take their resting pulse using the oximeter. Record your results in the table below. 2. The subject will then take three deep breaths before bending at the waist to submerge their face in the cold water. 3. The tester will start timing for 30 seconds once the subject has placed their face in the water. 4. The recorder will monitor the heart rate of the subject and note any changes. 5. At 30 seconds, the tester will tap the subject on the shoulder to end the testing period. 6. Change partners and repeat. Record your results below. +-------------+-------------+-------------+-------------+-------------+ | | NAME | EFFECTOR | NORMAL | YOUR | | | | | RESPONSE | RESPONSE | +=============+=============+=============+=============+=============+ | somatic | Achilles | Gastrocnemi | slight | | | | | us | plantar | | | | | | flexion of | | | | | soleus | the foot | | +-------------+-------------+-------------+-------------+-------------+ | | Patellar | Vastus | slight | | | | | medialis | extension | | | | | | of the | | | | | Vastus | lower leg | | | | | lateralis | at the knee | | | | | | | | | | | Vastus | | | | | | intermedius | | | | | | | | | | | | Bicep | | | | | | femoris | | | +-------------+-------------+-------------+-------------+-------------+ | | Biceps | Biceps | slight | | | | | brachii | flexion of | | | | | | the forearm | | | | | | at the | | | | | | elbow | | +-------------+-------------+-------------+-------------+-------------+ | | Triceps | Triceps | slight | | | | | brachii | extension | | | | | | of the | | | | | | forearm at | | | | | | the elbow | | +-------------+-------------+-------------+-------------+-------------+ | superficial | Plantar | \-\-\-\-- | Normal in | | | / | flexion | | adults: | | | cutaneous | | | toes flex | | | | | | (curl) | | | | | | | | | | | | Abnormal in | | | | | | adults: | | | | | | Babinski | | | | | | sign (toes | | | | | | spread), | | | | | | however | | | | | | this is | | | | | | normal in | | | | | | children | | | | | | under 18 | | | | | | months. | | +-------------+-------------+-------------+-------------+-------------+ | autonomic/ | Salivary | Salivary | Produce | | | visceral | | glands | more saliva | | | | | | in acidic | | | | | | solution | | +-------------+-------------+-------------+-------------+-------------+ | | Pupillary | Iris | Constricts | | | | | | pupil | | +-------------+-------------+-------------+-------------+-------------+ | | Diving | Cardiac | Slows heart | | | | | muscle | rate | | +-------------+-------------+-------------+-------------+-------------+ To test if the nerve signals are sent and processed in a certain area of the brain or spinal cord. PART B: REFLEX VIDEOS ===================== **Stretch or Deep Tendon Reflexes (upper limb) File Name: motor\_n\_04.mov** Grading 0 -- Absent 1. 2. 3. 4. **Stretch or Deep Tendon Reflexes (lower limb) File Name: motor\_n\_09.mov** **Plantar Reflex File Name: motor\_n\_10.mov** **Stretch or Deep Tendon Reflexes (lower limb) File Name: motor\_ab\_09.mov** **Plantar Reflex File Name: motor\_ab\_10.mov**