Term Test 2 - Anatomy and Physiology PDF

**Term Test 2** **Week 5** 1. **Describe the general functions of each membrane type and give their location within the body.** - **Epithelial Membranes:** also called *covering* and *lining membranes*; exposed to air and is a dry membrane - **Mucous Membranes**: Lin...

**Term Test 2** **Week 5** 1. **Describe the general functions of each membrane type and give their location within the body.** - **Epithelial Membranes:** also called *covering* and *lining membranes*; exposed to air and is a dry membrane - **Mucous Membranes**: Line body cavities that open to the outside (e.g., hollow organs of the respiratory, digestive, urinary and reproductive tracts). They secrete mucus, which lubricates and protects tissues. - **Composed of epithelium** (the type varies with the site) resting on a loose (areolar) connective tissue membrane called lamina *propria.* Mostly contain either stratified squamous epithelium (as in the mouth or esophagus) or simple columnar epithelium (as in the rest of the digestive tract). - In all cases, they are moist membranes that are almost continuously bathed in secretions or, in the case of the urinary mucosae, urine. - **Serous Membranes**: Line closed body cavities (e.g., pleura in the lungs, pericardium around the heart). They reduce friction between organs. - **Composed of one layer:** of simple squamous epithelium resting on a thin layer of areolar connective tissue. - **Line compartments** in the ventral body cavity that are closed to the exterior - **Occur in pairs --** the *parietal* layer lines a specific portion of the wall of the ventral body cavity; it folds in on itself to form the *visceral* layer, which covers the outside of the organ(s) in that cavity - **Serous layers** are separated not by air but by scanty amount of thin, clear fluid, called *serous fluid* which is secreted by both membranes - **Specific names** of the serous membranes depend on their locations: - The serosa lining the abdominal cavity and covering its organs is the **peritoneum** - In the thorax, serous membranes isolate the lungs and heart from one another - The membranes surrounding the lungs are the **pleurae** - Those around the heart are the **pericardia** - **Cutaneous Membrane**: The skin, covering the body's surface. It protects deeper tissues from injury, regulates temperature, and prevents water loss. - **Composed of two layers:** the superficial *epidermis* (composed of stratified squamous epithelium) and the underlying *dermis* (mostly dense irregular (fibrous) connective tissue) - **Connective Tissue Membranes** - **Synovial Membranes**: Line the cavities of joints. They secrete synovial fluid for lubrication. - **Composed of loose areolar connective tissue** and contain no epithelial cells at all - **Lines the fibrous capsules** surrounding joints, where they provide a smooth surface and secrete a lubricating fluid. They also line small sacs of connective tissue called *bursae* and the tubelike *tendon sheaths.* Both structures cushion organs moving against each other during muscle activity 2. **List and describe the functions of the integumentary system.** - Also called **integument** meaning **"covering",** insulated and cushions deeper body organs and protects the entire body from mechanical damage (bumps and cuts), chemical damage (such as from acids and bases), thermal damage (heat and cold), ultraviolet (UV) radiation (in sunlight), and microbes. - **Protection**: Acts as a barrier against pathogens, UV radiation, and dehydration. - **Regulation of Body Temperature**: Through sweat and blood vessel dilation/constriction. - **Sensory Perception**: Detects pain, temperature, and touch. - **Excretion**: Removes waste through sweat. - **Synthesis of Vitamin D**: UV light converts cholesterol into vitamin D in the skin. 3. **Identify and describe the tissue types found in the skin. (KNOW THIS DIAGRAM)** - **Epidermis**: made up of *stratified squamous epithelial* tissue that is capable of becoming hard and tough - **Dermis**: made up of mostly dense irregular connective tissue, containing blood vessels, nerves, and collagen. - **Hypodermis (Subcutaneous Layer)**: Mainly adipose tissue, providing insulation and cushioning. Also provides a site for nutrient storage and shock absorption 4. **Describe the structure and function of the layers of the skin.** - **Epidermis** - most cells of the epidermis are **keratinocytes** (keratin cells), which produce **keratin**, the fibrous protein that makes the epidermis a tough protective layer in a process called *keratinization* - Outermost layer providing protection - It is **avascular,** that is, it has no blood supply of its own - Composed of 5 layers or *strata* each with multiple layers of cells. From the inside out, these are: - **Stratum Basale:** stem cells are actively dividing; some newly formed cells become part of the more superficial layers - **Stratum Spinosum:** cells contain thick bundles of intermediate filaments made of pre-keratin - **Stratum Granulosum:** cells are flattened, organelles are deteriorating; cytoplasm full of granules - **Stratum Lucidum: (only found when skin is hairless and extra thick; i.e., the palms of the hand and soles of the feet);** cells begin to die - **Stratum Corneum:** cells are dead, flat membranous sacs filled with keratin. Glycolipids in extracellular space make skin water resistant - **Dermis**: Contains blood vessels, nerves, and glands, supporting skin functions like nourishment and sensory reception. - **Hypodermis**: Provides insulation, stores fat, and anchors the skin to underlying structures. 5. **Name the layers of the epidermis and describe the characteristics of each layer.** - **Stratum Corneum**: Outermost layer with dead, keratinized cells, providing waterproofing. Is 20 to 30 cell layers thick, but it accounts for about three-quarters of the epidermal thickness. - **Stratum Lucidum**: Found only in thick skin (palms, soles), providing extra protection. - **Stratum Granulosum**: Contains cells with granules, starting to die and keratinize. - **Stratum Spinosum**: Provides strength and flexibility, where keratin synthesis begins. - **Stratum Basale**: Deepest layer with mitotically active cells; responsible for skin regeneration. 6. **Name the layers of the dermis and describe the characteristics of each layer.** - **Papillary Layer:** Is the thin superficial dermal region. It is uneven and has peglike projections from its superficial surface, called *dermal papillae* which indent the epidermis above and help increase friction, enhance grip, and provide sensory receptors. - **Reticular Layer:** Is thick and the deepest skin layer containing dense connective tissue, collagen, and elastin, providing strength and elasticity. As well as blood vessels, sweat and oil glands, and deep pressure receptors called *lamellar corpuscles*. 7. **Identify the factors that determine skin color and describe the function of melanin.** - **Melanin:** A pigment that ranges in color from yellow to brown to black. Pigment produced by melanocytes, providing skin color and protection against UV radiation. - **Hemoglobin:** The amount of oxygen-rich hemoglobin (pigment in red blood cells) in the dermal blood vessels. It gives the skin a reddish hue due to blood flow. In light-skinned people, the crimson color of oxygen-rich hemoglobin in the dermal blood supply flushes through the transparent cell layers above and gives the skin a rosy glow. - **Carotene:** Contributes to yellow-orange pigmentation which is plentiful in carrots and other orange, deep yellow, or leafy green vegetables. People who eat large amounts of carotene-rich foods, their skin tend to take on a yellow-orange cast. 8. **Describe the basic structure and functions of the appendages of the skin.** - **Cutaneous Glands:** are all *exocrine glands* that release their secretions to the skim - **Sebaceous (Oil) Glands** - Are found all over the skin, except on the palms of the hands and soles of the feet - Their ducts usually empty into a hair follicle, but some open directly onto the skin surface. - **Function:** Produce sebum, lubricating (which keeps the skin soft and moist) and waterproofing the skin and hair which prevents it from becoming brittle. Additionally, sebum also contains chemicals that kill bacteria, so it is important in preventing bacterial infection of the skin. - **Sudoriferous (Sweat) Glands** - Are widely distributed in the skin - **There are two types:** *eccrine* and *apocrine* a. **Eccrine Glands:** are far more numerous and are found all over the body. They produce sweat and are an important and highly efficient part of the body's heat-regulating equipment b. **Apocrine Glands:** are largely confined to the axillary (armpit) and genital areas of the body. They are usually larger than eccrine glands, and their ducts empty into hair follicles. They begin to function during puberty under the influence of androgens. They play a minimal role in aiding in thermoregulation and waste excretion. Their precise function is not yet known, but they are activated by nerve fibers during pain and stress and during sexual arousal. 9. **Describe the role the integumentary system plays in maintaining homeostasis of body temperature and apply this knowledge.** - **Sweat Glands**: Release sweat to cool the body through evaporation. - **Blood Vessels**: Dilate to release heat such as evaporation of perspiration off the skin surface or constrict to conserve heat such as by shivering during cold weather. 10. **Describe the effects of aging on the skin.** - **Thinning of Epidermis:** Makes skin more fragile, makes it more susceptible to bruising and other types of injuries - **Reduced Elasticity:** along with loss of subcutaneous fat, allows bags to form under our eyes, and our jowls begin to sag causing wrinkles - **Drier Skin:** due to decrease in oil and sweat production - **Slower Healing:** Decreased cell turnover and blood flow 11. **Describe the homeostatic relationship between the integumentary system and other body systems.** - **Immune System:** Acts as a first barrier to pathogens. - **Skeletal System:** Synthesizes vitamin D for calcium absorption. - **Nervous System:** Sensory receptors detect environmental changes. - **Circulatory System:** Helps in temperature regulation through blood vessel dilation/constriction. **Week 5 (Part 2)** 1. **Define the three specific functions of the nervous system.** - **Sensory Input:** The nervous system detects stimuli from the environment or internal conditions using sensory receptors - **Integration:** It processes sensory information and determines an appropriate response - **Motor Output:** It triggers an action or response by activating muscles or glands 2. **Describe the organization of the nervous system, including the structural and functional classifications.** - **Structural Classification** - **Central Nervous System (CNS):** Composed of the brain and spinal cord which occupy the dorsal cavity; responsible for processing information. - **Peripheral Nervous System (PNS):** Contains cranial and spinal nerves. Includes all neural structures outside the CNS (nerves, ganglia), transmitting signals between the CNS and the body - **Functional Classification** - **Sensory (Afferent) Division**: Carries information from sensory receptors **TO** the CNS. The sensory division keeps the CNS constantly informed of events going on both inside and outside the body. - **Motor (Efferent) Division**: Carries instructions **FROM** the CNS to effector organs (muscles, glands) - **Somatic Nervous System (SNS)**: Controls *voluntary* movements of skeletal muscles. - **Autonomic Nervous System (ANS)**: Regulates *involuntary* functions, such as heart rate and digestion. i. **Sympathetic Division**: Activates the fight-or-flight response. ii. **Parasympathetic Division**: Promotes rest and digestion. 3. **Describe the basic structures and functions of neuroglia types.** - **Neuroglia ("nerve glue"):** aka glial cells or glia are supporting cells in the CNS that are lumped together. Neuroglia includes many types of cells that support, insulate, and protect the delicate neurons. In addition, each of the different types of neuroglia has special functions as stated below: - **Astrocytes:** are abundant star-shaped cells that account for nearly half of neural tissue. They support neurons and maintain the blood-brain barrier. - **Microglia:** are spiderlike phagocytes that monitor the health of nearby neurons and act as immune cells in the CNS by disposing of debris, such as dead brain cells and bacteria. - **Ependymal Cells:** Line the central cavities of the brain and spinal cord. They participate in the production of cerebrospinal fluid (CSF) and the beating of their cilia helps to circulate the CSF that fills those cavities and forms a protective watery cushion around the CNS. - **Oligodendrocytes:** are neuroglia that wrap their flat extensions (processes) tightly around CNS nerve fibers, producing fatty insulating coverings called *myelin sheaths.* - **Schwann Cells:** form the myelin sheaths around nerve fibers in the PNS - **Satellite Cells:** act as protective, cushioning cells for peripheral neuron cell bodies 4. **Describe the general structure of a neuron and identify its important anatomical regions.** - **Cell Body (Soma)** - **Structure:** The central part of the neuron, containing the nucleus, cytoplasm, and various organelles like the endoplasmic reticulum and mitochondria. - **Function:** The soma maintains the cell's health, integrates incoming signals from the dendrites, and is responsible for most of the neuron's metabolic activities. It plays a critical role in synthesizing proteins and neurotransmitters needed for neural communication. - **Dendrites** - **Structure:** Short, branching extensions from the cell body, forming a tree-like structure. - **Function:** Dendrites receive signals (mainly chemical or electrical) from other neurons and transmit these signals *toward* the cell body. They increase the surface area of the neuron, allowing it to receive input from multiple neurons. - **Axon** - **Structure:** A long, singular extension from the cell body, typically insulated with a myelin sheath in many neurons. - **Function:** The axon transmits electrical impulses (action potentials) *away* from the cell body toward other neurons, muscles, or glands. It is the primary conduction path for transmitting information over long distances within the nervous system. - **Axon Terminals** - **Structure:** The distal ends of the axon branch into multiple small extensions known as axon terminals or synaptic boutons. - **Function:** These terminals form synapses with other neurons, muscles, or glands, and release neurotransmitters into the synaptic cleft to transmit signals to the next cell. - **Myelin Sheath** - **Structure:** A fatty, insulating layer that wraps around the axon in segments, formed by Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS). - **Function:** The myelin sheath increases the speed of electrical transmission along the axon by preventing ion leakage and allowing the action potential to jump between gaps (Nodes of Ranvier) in a process called saltatory conduction. - **Nodes of Ranvier** - **Structure:** Small gaps between the segments of the myelin sheath along the axon. - **Function:** The Nodes of Ranvier allow the action potential to \"leap\" from one node to the next, speeding up the conduction process. These nodes also contain ion channels, which are critical for the recharging of the action potential as it propagates along the axon. 5. **Describe the composition of gray matter and white matter.** - **Gray Matter:** Contains mostly unmyelinated fibers and cell bodies. Composed mainly of neuron cell bodies and dendrites; involved in processing information. - **White Matter:** Consists of dense collections of myelinated fibers (tracts); responsible for transmitting signals over long distances. 6. **Classify neurons according to structure and function.** - **Structural Classification:** - **Multipolar Neurons:** Have one axon and multiple dendrites (common in the CNS). - **Bipolar Neurons:** One axon and one dendrite (found in sensory organs like the retina or nose). They act in sensory processing as receptor cells. - **Unipolar Neurons:** A single process extending from the cell body (found in sensory neurons). Only the small branches at the end of the peripheral process are dendrites; while the remainder of the peripheral process and the central process function as the axon; thus, in this case, the axon actually conducts nerve impulses both toward *and* away from the cell body. Sensory neurons found in the PNS ganglia are unipolar. - **Functional Classification:** - **Sensory Neurons (Afferent):** Transmit signals from sensory receptors to the CNS. They keep us informed about what is happening both inside and outside the body. - **Motor Neurons (Efferent):** Carry signals from the CNS to muscles or glands. - **Interneurons:** Connect sensory and motor neurons within the CNS. 7. **Identify the types of general sensory receptors and describe their functions.** - **Free Nerve Endings (Pain and Temperature Receptors)** - **Location:** found throughout the skin, as well as in other tissues such as muscles, joints, and visceral organs - **Function**: These are the simplest types of sensory receptors, detecting **pain** (nociception), **temperature** (thermoreception), and **light touch**. They are unspecialized and have bare dendrites, making them highly sensitive to a range of stimuli. - **Type of receptor**: Mechanoreceptors, thermoreceptors, and nociceptors. - **Meissner's Corpuscle (Touch Receptor)** - **Location:** Found primarily in the dermal papillae (just beneath the epidermis) of glabrous skin (hairless skin), such as the fingertips, palms, soles of the feet, and lips. - **Function:** These receptors are highly sensitive to light touch and low-frequency vibration. They help in detecting textures and shapes, contributing to the sense of fine touch. - **Type of receptor:** Mechanoreceptor. - **Lamellar Corpuscle (Deep Pressure Receptor)** - **Location:** Found deep in the dermis and in the hypodermis, as well as in other tissues such as joints, tendons, and the pancreas. - **Function:** Lamellar corpuscles are sensitive to deep pressure and vibration. They respond quickly to changes in pressure and are particularly useful in sensing vibrations or tapping. - **Type of receptor:** Mechanoreceptor. - **Proprioceptor** - **Golgi Tendon Organ** - **Location:** Found in tendons, where muscle fibers attach to bone. - **Function:** Golgi tendon organs monitor tension within the tendon during muscle contraction. They help protect muscles and tendons from damage by triggering a reflex that relaxes the muscle when tension becomes too high. This prevents overexertion or injury. - **Type of receptor:** Proprioceptor (senses body position and muscle tension). - **Muscle Spindle** - **Location:** Found within skeletal muscles. - **Function:** Muscle spindles detect muscle stretch and provide information about muscle length to the central nervous system. They are essential for maintaining muscle tone and postural reflexes, contributing to proprioception by allowing the body to sense its position in space. - **Type of receptor:** Proprioceptor (senses body position and movement). 8. **Describe the electrical conditions of a resting neuron\'s membrane and explain how they are maintained.** - The plasma membrane at rest is inactive (polarized) - Fewer positive ions are inside the neuron's plasma membrane than outside - Potassium (K+) is the major positive ion inside the cell - Sodium (Na+) is the major positive ion outside the cell - The polarized membrane is more permeable to K+ than to Na+ - As long as the inside of the membrane is more negative (fewer positive ions) than the outside, the cell remains inactive 9. **Explain how a nerve impulse is generated and propagated along a neuron and apply this knowledge.** - **Depolarization:** When a neuron is stimulated, Na⁺ channels open, allowing Na⁺ to rush in, reducing the negative charge. - **Action Potential:** If the stimulus reaches the threshold, an action potential is generated, propagating along the axon. - **Propagation:** The action potential moves along the axon, jumping between the nodes of Ranvier (saltatory conduction). - **Repolarization:** K⁺ channels open, allowing K⁺ to exit, restoring the negative charge. 10. **Explain the role of neurotransmitters in nerve transmission across the synapse and apply this knowledge.** - Neurotransmitters are released from axon terminals into the synapse. - They bind to receptors on the postsynaptic neuron, triggering a response. - **Excitatory Neurotransmitters:** Increase the likelihood of the postsynaptic neuron firing. - **Inhibitory Neurotransmitters:** Decrease the likelihood of the postsynaptic neuron firing. 11. **Identify and explain the functions of the major brain regions of the cerebral hemispheres, diencephalon, brain stem, and cerebellum, and apply this knowledge.** - **Cerebral Hemispheres:** Responsible for higher functions (thinking, memory, voluntary movement) - **Cortex: Gray Matter** - Localizes and interprets sensory inputs - Controls voluntary and skilled skeletal muscle activity - Act in intellectual and emotional processing - **Basal Nuclei** - Subcortical motor centers help control skeletal muscle movements - **Diencephalon** - **Thalamus:** Relays sensory information. - Relays sensory impulses to cerebral cortex - Relays impulses between cerebral motor cortex and lower motor centers - Involved in memory - **Hypothalamus:** Regulates autonomic functions, homeostasis. - Chief integration center of autonomic (involuntary) nervous system - Regulates body temperature, food intake, water balance, and thirst - Regulates hormonal output of anterior pituitary gland and acts as an endocrine organ (producing ADH and oxytocin) - **Limbic System -- A functional system:** - Includes cerebral and diencephalon structures (e.g., hypothalamus and anterior thalamic nuclei) - Mediates emotional response; involved in memory processing - **Brain Stem:** Controls basic life functions. - **Midbrain:** Reflex actions. - Contains visual and auditory reflex centers - Contains subcortical motor centers - Contains nuclei for cranial nerves III and IV; contains projection fibers (e.g., fibers of the pyramidal tracts) - **Pons:** Relays signals between cerebrum and cerebellum. - Relays information from the cerebrum to the cerebellum - Cooperates with the medullary centers to control respiratory rate and depth - Contains nuclei of cranial nerves V-VII; contains projection fibers - **Medulla Oblongata:** Controls heart rate, breathing. - Relays ascending sensory pathway impulses from skin and proprioceptors - Contains nuclei controlling heart rate, blood vessel diameter, respiratory rate, vomiting, etc. - Relays sensory information to the cerebellum - Contains nuclei of cranial nerves VIII-XII; contains projection fibers - Site of crossover of pyramids - **Cerebellum** - **Cerebellum:** Coordinates voluntary movements and balance. - Processes information from cerebral motor cortex, proprioceptors, and visual and equilibrium pathways - Provides "instructions" to cerebral motor cortex and subcortical motor centers, resulting in smooth, coordinated skeletal muscle movements - Responsible for proper balance and posture 12. **Identify the three meninges and describe their functions.** - **Dura Mater: (**meaning "tough or hard mother") is the outermost, tough leathery layer. It is a double-layered membrane that surrounds the brain. - **Function:** Provides a strong, durable protective layer for the brain and spinal cord. It helps maintain the brain\'s position within the skull and limits excessive movement, reducing the risk of injury. It also contains large blood vessels that supply the brain. - **Arachnoid Mater:** Middle meningeal, web-like layer. - **Function:** Serves as a cushioning barrier. Beneath it lies the subarachnoid space, which is filled with cerebrospinal fluid (CSF). This space acts as a shock absorber for the brain and spinal cord, helping to protect them from impact or sudden movements. - **Pia Mater:** (meaning "gentle mother") is a thin, inner layer that clings to the surface of the brain and spinal cord. - **Function:** Acts as a permeable membrane, allowing for the exchange of nutrients and waste products between the brain and cerebrospinal fluid. It also provides support to blood vessels that nourish the tissues. 13. **Describe the composition and function of cerebrospinal fluid.** - **Composition:** A clear, watery fluid with components similar to blood plasma. - **Function:** In and around the brain and spinal cord forms a watery cushion that protects the fragile nervous tissue from blows and other trauma and helps the brain "float", so it is not damaged by the pressure of its own weight. It also helps with providing nutrients and removing waste. 14. **Describe the structure and function of the blood-brain barrier.** - **Structure:** composed of the *least* permeable capillaries in the whole body. These capillaries are almost seamlessly bound together by tight junctions all around. - **Function:** Protects the brain from harmful substances (e.g., metabolic wastes, such as urea, toxins, proteins, and most drugs) in the bloodstream while allowing essential nutrients (e.g., water, glucose, and essential amino acids) to pass through. 15. **Describe the location, structure and functions of the spinal cord and spinal nerves.** - **Spinal Cord:** - **Location:** Extends from the vertebral column (spine), running from the base of the brain (medulla oblongata) down to the level of the first or second lumbar vertebra. Beyond this point, it tapers into a structure called the **conus medullaris**, with a bundle of nerve fibers extending further down, known as the **cauda equina**. - **Structure:** Contains gray matter in the center (butterfly shape) and white matter surrounding it. - **Gray Matter:** The inner region of the spinal cord, arranged in an \"H\" or butterfly shape, contains neuron cell bodies, dendrites, and unmyelinated axons. It has different regions: - **Dorsal (posterior) horn:** Receives sensory information from the body. - **Ventral (anterior) horn:** Sends motor signals to muscles. - **Lateral horn (present in the thoracic and upper lumbar regions):** Involved in autonomic functions (sympathetic nervous system). - **White Matter:** The outer region consists of myelinated axons that form ascending and descending tracts. These tracts carry information to and from the brain: - **Ascending tracts:** Carry sensory information from the body to the brain. - **Descending tracts:** Transmit motor commands from the brain to the body. - **Function:** Transmits signals between the brain and body, and coordinates reflexes. - **Spinal Nerves:** 31 pairs; each contains both sensory and motor fibers, linking the body to the CNS. - **Location:** Spinal nerves emerge from the spinal cord through spaces between the vertebrae, known as intervertebral foramina. There are 31 pairs of spinal nerves, organized into groups according to the regions of the vertebral column: - **Cervical (8 pairs):** C1--C8 - **Thoracic (12 pairs):** T1--T12 - **Lumbar (5 pairs):** L1--L5 - **Sacral (5 pairs):** S1--S5 - **Coccygeal (1 pair):** Co1 - **Structure:** formed when dorsal and ventral roots merge - Each spinal nerve is a **mixed nerve**, containing both sensory and motor fibers: - **Dorsal root**: Contains sensory (afferent) fibers that carry information from sensory receptors (e.g., skin, muscles) to the spinal cord. Each dorsal root has a **dorsal root ganglion**, which contains the cell bodies of sensory neurons. - **Ventral root**: Contains motor (efferent) fibers that transmit signals from the spinal cord to muscles and glands. - The dorsal and ventral roots merge to form a spinal nerve, which then branches out to innervate specific regions of the body. - **Function:** - **Sensory Function**: Spinal nerves carry sensory information from the peripheral receptors (such as skin, muscles, and joints) to the spinal cord, which then relays the signals to the brain for processing. - **Motor Function**: Motor signals from the brain are transmitted through the spinal cord to the spinal nerves, which then innervate muscles to control voluntary movements. - **Autonomic Functions**: Some spinal nerves, particularly in the thoracic and lumbar regions, contain autonomic fibers that regulate involuntary activities, such as heart rate, digestion, and glandular secretions. **Week 6** 1. **Describe the structure of a nerve and distinguish between sensory, motor and mixed nerves.** - **Structure:** - **Endoneurium:** Surrounds individual nerve fibers (axons). - **Perineurium:** Encloses bundles of nerve fibers (fascicles). - **Epineurium:** Encases the entire nerve, which may contain multiple fascicles. - **Types of Nerves:** - **Sensory Nerves:** Contain only sensory (afferent) fibers, transmitting information from receptors to the CNS. - **Motor Nerves:** Contain only motor (efferent) fibers, transmitting commands from the CNS to muscles or glands. - **Mixed Nerves:** Contain both sensory and motor fibers, transmitting signals in both directions. 2. **Identify the cranial nerves by number and by name and describe the major functions of each.** - **I. Olfactory:** Smell. - **Function:** Purely sensory; carries impulses for the sense of smell - **II. Optic:** Vision. - **Function:** Purely sensory; carries impulses for vision - **III. Oculomotor:** Eye movement, pupil constriction. - **Function:** Purely motor; supplies motor fibers to four of the six muscles (superior, inferior, and medial rectus, and inferior oblique) that direct the eyeball; and to the internal eye muscles controlling lens shape and pupil size - **IV. Trochlear:** Eye movement (superior oblique muscle). - **Function:** Purely motor; supplies motor fibers for one external eye muscle (superior oblique) - **V. Trigeminal:** Sensation from the face, mouth, and chewing muscles. - **Function:** Mixed nerve; conducts sensory impulses from the skin of the face and mucosa of the nose, mouth, and corneas; also contains motor fibers that activate the chewing muscles - **VI. Abducens:** Eye movement (lateral rectus muscle). - **Function:** Purely motor; supplies motor fibers to the lateral rectus muscle, which rolls the eye laterally - **VII. Facial:** Facial expression, taste (anterior 2/3 of the tongue), tear and saliva secretion. - **Function:** Mixed nerve; activates the muscles of facial expression and the lacrimal and salivary glands; carries sensory impulses from the taste buds of anterior tongue - **VIII. Vestibulocochlear:** Hearing and balance. - **Function:** Mixed nerve vestibular branch transmits impulses for the sense of balance, and cochlear branch transmits impulses for the sense of hearing; small motor component adjusts sensitivity of sensory receptors - **IX. Glossopharyngeal:** Taste (posterior 1/3 of the tongue), swallowing, and saliva secretion. - **Function:** Mixed nerve; supplies motor fibers to the pharynx (throat) that promote swallowing and saliva production; carries sensory impulses from taste buds of the posterior tongue and from chemical and pressure receptors of the carotid artery - **X. Vagus:** Autonomic control of the heart, lungs, digestive organs; sensory input from internal organs. - **Function:** Mixed nerve; fibers carry sensory impulses from and motor impulses from and motor impulses to the pharynx, larynx, and the abdominal and thoracic viscera; most motor fibers are parasympathetic fibers that promote digestive activity to help regulate heart activity - **XI. Accessory:** Controls neck and shoulder muscles. - **Function:** Purely motor fibers activate the sternocleidomastoid and trapezius muscles - **XII. Hypoglossal:** Tongue movement. - **Function:** Purely motor fibers control tongue movements 3. **Identify the number and location of the spinal nerves.** - **31 Pairs of Spinal Nerves**: - **Cervical**: 8 pairs (C1--C8). - **Thoracic**: 12 pairs (T1--T12). - **Lumbar**: 5 pairs (L1--L5). - **Sacral**: 5 pairs (S1--S5). - **Coccygeal**: 1 pair (Co1). 4. **Describe the origin and fiber composition of spinal nerves, including the ventral and dorsal roots.** - **Ventral Roots:** Carry motor (efferent) fibers from the spinal cord to muscles or glands. - **Dorsal Roots:** Contain sensory (afferent) fibers that bring information from the body to the spinal cord. - **Spinal Nerve:** A mixed nerve formed by the merging of the dorsal and ventral roots, carrying both sensory and motor fibers. 5. **Describe a reflex arc and explain its five basic elements.** - **Receptor:** Reacts to a stimulus - **Sensory Neuron:** Carries message to the integration center - **Integration Center:** Processes the information and directs motor output - **Motor Neuron:** Carries message to an effector - **Effector:** Muscle or gland that responds to the motor signal 6. **Define and describe the structure and function of the autonomic nervous system.** - **Structure:** Part of the PNS that controls involuntary functions. It has two branches: sympathetic and parasympathetic. - **Function:** Regulates vital bodily functions like heart rate, digestion, and respiration, usually without conscious control. 7. **Distinguish between the sympathetic and parasympathetic divisions and describe their respective effects on specific organs.** - **Sympathetic Division (\"Fight-or-Flight\"):** - Increases heart rate, dilates pupils, dilates airways, inhibits digestion. - Releases norepinephrine and epinephrine. - **Parasympathetic Division (\"Rest-and-Digest\"):** - Slows heart rate, constricts pupils, stimulates digestion, constricts airways. - Releases acetylcholine. 8. **Identify and differentiate the types of receptors in the autonomic nervous system, including their locations.** - **Adrenergic Receptors:** Bind norepinephrine and epinephrine. - **Alpha Receptors:** Found in blood vessels, controlling vasoconstriction. - **Beta Receptors:** Found in the heart (beta-1) and lungs (beta-2), affecting heart rate and bronchodilation. - **Cholinergic Receptors:** Bind acetylcholine. - **Nicotinic Receptors:** Found at neuromuscular junctions and ganglia, stimulating muscle contraction. - **Muscarinic Receptors:** Found in parasympathetic target organs, affecting heart rate and glandular secretions. 9. **Describe the effects of aging on the anatomy and physiology of the nervous system.** - **Sympathetic nervous system gradually become less and less efficient, particularly in its ability to constrict blood vessels** - **Orthostatic Hypotension:** results in changes in body position, in this case the sympathetic nervous system is not able to react quickly enough to counteract the pull of gravity by activating the vasoconstrictor fibers, and blood pools in the feet - **Circulatory system problems, which is the usual cause of nervous system deterioration** - **Arteriosclerosis:** which is a decreased elasticity of the arteries and high blood pressure causing a reduction in the supply of oxygen to brain neurons which can lead to **senility**, which is characterized by forgetfulness, irritability, difficulty in concentrating and thinking clearly, and confusion or in extreme cases, a sudden loss of blood and oxygen delivery to the brain can result in a stroke. - **Neuronal Loss:** Decreased number of neurons leads to slower processing and reflexes. - **Reduced Synaptic Plasticity:** Diminished ability to form new connections, affecting learning and memory. - **Decreased Neurotransmitter Production:** Results in slower communication between neurons. - **Demyelination:** Slows down signal conduction, impacting motor and cognitive functions. 10. **Describe the homeostatic relationship between the nervous system and other body systems.** - **Endocrine System**: Works with the hypothalamus and autonomic system to regulate hormones. - **Muscular System**: Nerves control voluntary and involuntary muscle activity. - **Cardiovascular System**: Regulates heart rate and blood pressure through the autonomic nervous system. - **Respiratory System**: Controls breathing rate in response to CO₂ levels. - **Digestive System**: ANS regulates the movement of the digestive tract and enzyme secretion.