HSF 2 Test 1(4).pdf

HSF TEST 1 Special Senses 1. Describe the structure and function of accessory eye structures, eye layers, the lens, and humors of the eye. 2. Outline the causes and consequences of cataracts and glaucoma. 3. Trace the pathway of light through the eye to the retina, and explain how light is focused f...

HSF TEST 1 Special Senses 1. Describe the structure and function of accessory eye structures, eye layers, the lens, and humors of the eye. 2. Outline the causes and consequences of cataracts and glaucoma. 3. Trace the pathway of light through the eye to the retina, and explain how light is focused for distant and close vision. 4. Outline the causes and consequences of astigmatism, myopia, hyperopia, and presbyopia. 5. Describe the events that convert light into a neural signal. 6. Compare and contrast the roles of rods and cones in vision. 7. Compare and contrast light and dark adaptation. 8. Trace the visual pathway to the visual cortex, and briefly describe the steps in visual processing. 9. Describe the location, structure, and afferent pathways of smell receptors, and explain how these receptors are activated. 10. Describe the location, structure, and afferent pathways of taste receptors, and explain how these receptors are activated. 11. Describe the structure and general function of the outer, middle, and internal ears. 12. Describe the sound conduction pathway to the fluids of the internal ear. 13. Describe sound transduction. 14. Describe the pathway of impulses traveling from the cochlea to the auditory cortex. 15. Explain how we are able to differentiate pitch and loudness, and to localize the source of sounds. 16. Explain how the balance organs of the semicircular canals and the vestibule help maintain equilibrium. 17. List possible causes and symptoms of otitis media, deafness, and Ménière’s syndrome. Special Senses answers 1. Accessory eye structures, like the eyelids and eyelashes, play crucial roles in safeguarding the eye. Eyelids act as protective barriers, preventing foreign particles and excessive light from entering the eye. Meanwhile, eyelashes help shield the eye from debris and direct airflow, contributing to the overall protection of this sensitive organ. Eye layers encompass the outermost sclera, which maintains the eye’s structural integrity, the middle choroid, responsible for nourishing the eye’s tissues, and the inner retina, containing photoreceptor cells essential for vision. The lens, a transparent, flexible structure, fine-tunes the focus of incoming light onto the retina. Humors, including aqueous and vitreous humors, maintain the eye’s shape and optical properties. 2. Cataracts, characterized by the clouding of the eye’s lens, obstruct light passage, leading to blurred vision and visual impairment. The causes range from aging to genetic predispositions and environmental factors. Glaucoma, on the other hand, involves elevated intraocular pressure, potentially damaging the optic nerve. If left untreated, it can progress to irreversible vision loss. 3. Light’s journey through the eye begins as it enters the cornea, a transparent outer layer. Passing through the aqueous humor, the lens adjusts its shape to focus light onto the retina. The vitreous humor maintains the eye’s spherical shape. Accommodation, a process involving changes in lens shape, optimizes vision for different distances. 4. Astigmatism results from irregular corneal curvature, causing distorted vision. Myopia, or nearsightedness, occurs when distant objects appear blurry, while hyperopia, or farsightedness, affects close vision. Presbyopia, an age-related condition, diminishes the eye’s ability to focus on nearby objects due to lens stiffness. 5. Phototransduction, the conversion of light into neural signals, involves photoreceptor cells in the retina, specifically rods and cones. Rhodopsin, a light-sensitive pigment, initiates a cascade of events leading to the generation of electrical signals. 6. Rods, concentrated in the retina’s periphery, excel in low-light conditions and motion detection. Cones, primarily in the central fovea, facilitate color vision and detailed perception, offering optimal visual acuity in well-lit environments. 7. Light adaptation occurs when the eyes adjust to increased brightness, involving the constriction of pupils and decreased sensitivity. Dark adaptation, conversely, involves the eyes becoming more sensitive to low-light conditions over time. 8. The visual pathway starts with signals traveling from the retina via the optic nerve, optic chiasm, and optic tract. Visual processing in the brain includes feature extraction, where specific aspects like edges and motion are identified, and pattern recognition, enabling the brain to interpret complex visual stimuli. 9. Smell receptors, situated in the olfactory epithelium within the nasal cavity, are activated when odor molecules bind to specific receptors. This initiates a neural signal that travels to the olfactory bulb and further into the brain’s olfactory centers. 10. Taste receptors, housed in taste buds on the tongue and other oral surfaces, respond to distinct taste qualities. Sweet, sour, salty, bitter, and umami tastes are perceived through molecular interactions that activate specific receptors. 11. The outer ear captures sound waves through the pinna, directing them into the ear canal. The middle ear, comprising the tympanic membrane and ossicles (malleus, incus, stapes), amplifies and transmits these sound waves. The inner ear, encompassing the cochlea, vestibule, and semicircular canals, converts sound into electrical signals for the brain. 12. Sound conduction involves the tympanic membrane vibrating in response to sound waves, causing the ossicles to transmit these vibrations to the fluids of the internal ear. This intricate process ensures the efficient transmission of auditory information. 13. Sound transduction occurs in the cochlea, where hair cells convert mechanical vibrations into electrical signals. These signals are then transmitted via the auditory nerve for further processing in the brain. 14. Auditory impulses travel from the cochlea to the auditory cortex, passing through the auditory nerve and thalamus. Along this pathway, the brain interprets various aspects of sound, contributing to our perception of complex auditory stimuli. 15. Differentiating pitch and loudness involves the brain interpreting the frequency and amplitude of sound waves. Localization of sound sources is achieved through the brain’s ability to process subtle differences in sound arrival times at each ear. 16. Balance organs in the semicircular canals and the vestibule help maintain equilibrium by detecting changes in head position and movement. These structures, filled with fluid and sensory hair cells, provide the brain with essential information about spatial orientation. 17. Otitis media, an inflammation of the middle ear, may be caused by infections and presents symptoms like ear pain and hearing difficulties. Deafness can result from various factors, including genetics, trauma, or exposure to loud noises. Ménière’s syndrome, characterized by fluid imbalance in the inner ear, manifests as vertigo, hearing loss, and ringing in the ears. Symptoms can vary in intensity and duration. Endocrine system 1. Indicate important differences between hormonal and neural controls of body functioning. 2. List the major endocrine organs, and describe their body locations. 3. Distinguish between hormones, paracrines, and autocrines. 4. Describe how hormones are classified chemically. 5. Describe the two major mechanisms by which hormones bring about their effects on their target tissues 6. Explain how hormone release is regulated. 7. Identify factors that influence activation of a target cell by a hormone. 8. List three kinds of interaction of different hormones acting on the same target cell. 9. Describe structural and functional relationships between the hypothalamus and the pituitary gland. 10. Discuss the structure of the posterior pituitary, and describe the effects of the two hormones it releases. 11. List and describe the chief effects of anterior pituitary hormones. 12. Describe the effects of the two groups of hormones produced by the thyroid gland. 13. Follow the process of thyroxine formation and release. 14. Indicate general functions of parathyroid hormone. 15. List hormones produced by the adrenal gland, and cite their physiological effects 16. Briefly describe the importance of melatonin 17. Compare and contrast the effects of the two major pancreatic hormones. 18. Describe the functional roles of hormones of the testes, ovaries, and placenta. 19. State the location of enteroendocrine cells. 20. Briefly explain the hormonal functions of the heart, kidney, skin, adipose tissue, bone, and thymus. 1. Hormonal vs. Neural Controls: - Hormonal Control: Operates on a slower timescale, allowing for sustained and widespread effects throughout the body. Hormones travel in the bloodstream, influencing various target cells simultaneously. - Neural Control: Functions rapidly, transmitting electrical signals through nerves. This mode is well-suited for precise, immediate responses, particularly in situations requiring quick adjustments. 2. Major Endocrine Organs and Locations: - Hypothalamus: Beyond hormonal regulation, it integrates nervous and endocrine systems, influencing various physiological processes such as temperature control and hunger regulation. - Pituitary Gland: Acts as a nexus for endocrine regulation, releasing hormones that govern other endocrine organs, exerting a masterful influence on the body's homeostasis. 3. Hormones, Paracrines, Autocrines: - Hormones:Include diverse molecules like insulin, cortisol, and thyroid hormones, which, when released into the bloodstream, orchestrate complex physiological responses across multiple organs. - Paracrines and Autocrines: Facilitate local communication within tissues, ensuring coordination in specific regions without the need for systemic involvement. 4. Chemical Classification of Hormones: - Amino Acid-based Hormones: Peptides, proteins, and amines such as insulin and growth hormone, orchestrate cellular responses through receptor-mediated mechanisms. - Steroids: Derived from cholesterol, hormones like cortisol and sex hormones regulate processes at the cellular level. 5. Mechanisms of Hormone Action: - Receptor-Mediated Actions: Hormones bind to specific receptors on target cell surfaces, initiating intracellular processes that lead to a cellular response. - Second Messenger Systems: Intracellular messengers, like cAMP or calcium ions, amplify and transmit hormonal signals, ensuring a robust and coordinated cellular response. 6. Regulation of Hormone Release: - Feedback Mechanisms: Negative feedback ensures that hormone levels remain within a narrow range, preventing overproduction. Positive feedback, while less common, can enhance specific physiological processes. 7. Factors Influencing Target Cell Activation: - Receptor Sensitivity: The responsiveness of target cells is influenced by the number and sensitivity of hormone receptors. - Hormone Concentration: The concentration gradient in the bloodstream determines the intensity of the hormonal effect. - Interactions with Other Substances: Co-factors, co-receptors, or other signaling molecules can modulate the cellular response to hormones. 8. Interactions of Different Hormones: - Permissive Interactions: One hormone enhances the response of another, demonstrating the synergistic nature of hormonal regulation. - Antagonistic Interactions: Hormones with opposing effects, like insulin and glucagon, maintain a delicate balance. - Synergistic Interactions: Multiple hormones acting together to produce a more pronounced effect, exemplified by FSH and testosterone working together in spermatogenesis. 9. Hypothalamus-Pituitary Relationship: - The hypothalamus, a crucial brain region, releases releasing and inhibiting hormones that regulate the anterior pituitary's secretion, illustrating the intricate coordination between the central nervous system and endocrine system. 10. Posterior Pituitary: - The posterior pituitary, an extension of the hypothalamus, stores and releases oxytocin and vasopressin. Oxytocin fosters social bonding and maternal behaviors beyond its reproductive roles, emphasizing the diverse effects of hormones. 11. Anterior Pituitary Hormones: - Each anterior pituitary hormone, such as growth hormone and follicle-stimulating hormone, plays a distinct role in regulating physiological processes, demonstrating the specialization and specificity of endocrine function. 12. Thyroid Gland Hormones: - Thyroid hormones, thyroxine (T4) and triiodothyronine (T3), intricately control metabolism, growth, and development, underscoring their pivotal role in maintaining overall homeostasis. 13. Thyroxine Formation and Release: - The process involves the intricate synthesis and release of thyroid hormones, finely regulated by the hypothalamus and pituitary gland, emphasizing the delicate balance required for hormonal regulation. 14. Parathyroid Hormone (PTH): - PTH, released by the parathyroid glands, maintains calcium and phosphate balance in the blood, demonstrating the importance of endocrine regulation in mineral homeostasis. 15. Adrenal Gland Hormones: - The adrenal cortex produces cortisol, which regulates metabolism and immune response, while aldosterone influences electrolyte balance. The adrenal medulla releases epinephrine and norepinephrine, showcasing the diverse effects of adrenal hormones on various physiological systems. 16. Importance of Melatonin: - Beyond regulating sleep-wake cycles, melatonin influences mood and exhibits antioxidant properties, illustrating the multifaceted roles of hormones in maintaining overall health. 17. Pancreatic Hormones: - Insulin facilitates glucose utilization, and glucagon mobilizes glucose reserves, illustrating the concerted efforts of pancreatic hormones in maintaining glucose homeostasis. 18. Gonadal and Placental Hormones: - Hormones from the testes, ovaries, and placenta regulate reproductive processes, fetal development, and maternal adaptations during pregnancy, emphasizing the vital role of endocrine regulation in the continuity of life. 19. Location of Enteroendocrine Cells: - Scattered throughout the gastrointestinal tract, enteroendocrine cells release hormones influencing digestion, nutrient absorption, and glucose regulation, showcasing the integration of endocrine functions in metabolic processes. 20. Hormonal Functions of Various Tissues: - The heart, kidney, skin, adipose tissue, bone, and thymus each contribute to hormonal regulation in unique ways, highlighting the interconnectedness of endocrine functions with cardiovascular health, metabolism, immune response, and overall homeostasis. Blood 1. List the functions of blood. 2. Describe the composition and physical characteristics of whole blood. Explain why it is classified as a connective tissue. 3. Discuss the composition and functions of plasma. 4. Describe the structure, function, and production of erythrocytes. 5. Describe the chemical composition of hemoglobin. 6. Give examples of disorders caused by abnormalities of erythrocytes. Explain what goes wrong in each disorder. 7. List the classes, structural characteristics, and functions of leukocytes. 8. Describe how leukocytes are produced. 9. Give examples of leukocyte disorders, and explain what goes wrong in each disorder. 10. Describe the structure and function of platelets 11. Describe the process of hemostasis. List factors that limit clot formation and prevent undesirable clotting. 12. Give examples of hemostatic disorders. Indicate the cause of each condition. 13. Describe the ABO and Rh blood groups. Explain the basis of transfusion reactions. 14. Describe fluids used to replace blood volume and the circumstances for their use. 15. Explain diagnostic importance of blood testing 16. How does hematopoiesis work? Blood (answers) 1. Blood functions include oxygen transport, nutrient delivery, waste removal, immune defense, clotting, and regulation of body temperature and pH. 2. Whole blood is composed of plasma and formed elements (erythrocytes, leukocytes, and platelets). Classified as connective tissue due to cells suspended in an extracellular matrix (plasma). 3. Plasma is a straw-colored liquid containing water, electrolytes, proteins, hormones, and waste products. Functions include nutrient and waste transport, immune response, and clotting support. 4. Erythrocytes (red blood cells) transport oxygen. Biconcave disc shape increases surface area, lacks a nucleus, and produced in the bone marrow. 5. Hemoglobin, the oxygen-carrying protein in erythrocytes, consists of four globin protein chains and heme groups containing iron. 6. Disorders like anemia (low RBCs), sickle cell anemia (abnormal hemoglobin), and polycythemia (excess RBCs) affect erythrocytes. 7. Leukocytes (white blood cells) are divided into granulocytes and agranulocytes, with functions including immune response and defense against pathogens. 8. Leukocytes are produced in the bone marrow through hematopoiesis. 9. Leukocyte disorders include leukemia (uncontrolled WBC production) and neutropenia (low neutrophil count), affecting immune function. 10. Platelets aid in clotting by forming a temporary plug at injury sites. 11. Hemostasis involves vasoconstriction, platelet plug formation, and coagulation. Factors limiting clot formation include anticoagulants and fibrinolysis. 12. Hemostatic disorders include hemophilia (clotting factor deficiency) and thrombosis (undesirable clot formation). 13. ABO and Rh blood groups involve antigens on RBCs. Transfusion reactions occur if mismatched blood is transfused. 14. Fluids like saline or plasma expanders replace blood volume in cases of hemorrhage or dehydration. 15. Blood testing aids in diagnosing conditions, measuring blood cell counts, identifying infections, and assessing organ function. 16. Hematopoiesis is the process of blood cell formation that occurs primarily in the bone marrow. Here's a simplified overview: Hematopoietic Stem Cells (HSCs): These are undifferentiated cells with the potential to become various blood cell types. They reside in the bone marrow. Multi-potent Progenitor Cells: HSCs give rise to multipotent progenitor cells that can differentiate into either myeloid or lymphoid progenitor cells. Myeloid Progenitor Cells: Differentiate into various myeloid cells, including red blood cells, platelets, monocytes, neutrophils, eosinophils, and basophils. Lymphoid Progenitor Cells: Give rise to lymphocytes, including T cells, B cells, and natural killer (NK) cells. Maturation and Circulation: The differentiated cells undergo further maturation, and functional blood cells are released into the bloodstream to perform their specific roles in the immune system (lymphocytes) or in oxygen transport and clotting (myeloid cells). This continuous and regulated process ensures the production of a balanced and functional array of blood cells to maintain homeostasis and respond to the body's needs. Cytokines, growth factors, and other signaling molecules play crucial roles in regulating hematopoiesis at various stages. Extra stuff Adrenocorticotropic Hormone (ACTH) is a peptide hormone that plays a crucial role in the regulation of the adrenal cortex. Here's an overview: Structure: ACTH is a polypeptide hormone and is part of the proopiomelanocortin (POMC) family of peptides. POMC is a precursor molecule that is enzymatically cleaved to yield various bioactive peptides, including ACTH. Functions: 1. Stimulation of Cortisol Production:ACTH primarily stimulates the adrenal cortex to produce and release cortisol, a glucocorticoid hormone involved in various physiological processes such as metabolism, immune response, and stress regulation. Regulation and Production: 1. Hypothalamus-Pituitary-Adrenal (HPA) Axis: ACTH is regulated by the hypothalamus-pituitaryadrenal axis. The hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the pituitary gland to release ACT 2. Negative Feedback: Cortisol, the end product of ACTH action, exerts negative feedback on the HPA axis. Elevated cortisol levels signal the hypothalamus and pituitary to reduce the release of CRH and ACTH, respectively, maintaining a delicate balance. 3. Circadian Rhythm and Stress: ACTH secretion follows a circadian rhythm, peaking in the early morning. Additionally, stress can trigger an increased release of ACTH and cortisol. Understanding ACTH's regulation is essential for comprehending its role in responding to stress, maintaining homeostasis, and contributing to the body's adaptation to various physiological challenges.