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This document appears to be a study guide or chapter from a textbook on the autonomic nervous system. It contains information about the functions and features of the autonomic nervous system.
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. Structural and Functional Differences Between ANS 3 tudy Guide: Chapter 15 – The Autonomic S...
. Structural and Functional Differences Between ANS 3 tudy Guide: Chapter 15 – The Autonomic S and Somatic Nervous System (SNS) Nervous System (ANS) Feature Autonomic Nervous System (ANS) Somatic Nervous System (SNS) Textbook Reference: Saladin Anatomy and Physiology,10th edition Control Involuntary Voluntary Motor Pathway wo neurons: preganglionic and T ne neuron (CNS → skeletal O postganglionic muscle) . Functions and Features of the Autonomic Nervous 1 Ganglia Present (autonomic ganglia) Absent System (ANS) Effector Organs Smooth/cardiac muscles, glands Skeletal muscles D efinition: The ANS regulates involuntary processes,such as heart rate, digestion, respiration, and glandular secretion. eurotransmitter N ACh (PSNS); ACh & NE (SNS) Acetylcholine (ACh) Functions: s ○ Maintainshomeostasisby controlling visceral organs. ○ Operatesautomaticallywithout conscious effort. Effect Excitatory or inhibitory Always excitatory ○ Adjusts organ activity in response to internal or external changes. Key Features: ○ Divided intoSympathetic Nervous System (SNS)andParasympathetic Nervous System (PSNS). 4. Parasympathetic vs. Sympathetic Divisions of the ANS ○ Involvestwo-neuron pathways(preganglionic and postganglionicneurons). Feature Parasympathetic Division Sympathetic Division (SNS) ○ Influences smooth muscle, cardiac muscle, and glands. (PSNS) Origin in CNS raniosacral (brainstem and C Thoracolumbar (T1-L2 spinal cord) S2-S4 spinal cord) 2. Characteristics of Visceral Reflexes Ganglionic Fibers L ong preganglionic, short hort preganglionic, long S postganglionic postganglionic D efinition: Unconscious, automatic responses to stimulationinvolving visceral organs. Characteristics: eurotransmitter N cetylcholine (ACh) at both A Ch at preganglionic; NE A ○ Receptors detect internal changes (e.g., blood pressure, pH). s synapses (norepinephrine) at postganglionic ○ Afferent neurons carry signals to the CNS. synapse ○ Integrating centers in the CNS process the information. ○ Efferent pathways consist of two neurons (preganglionic and postganglionic). Receptors icotinic and muscarinic N icotinic (preganglionic) and N ○ Effectors are smooth/cardiac muscles or glands. receptors adrenergic (target) receptors Example:Baroreflex(regulation of blood pressure) ○ Receptor: Baroreceptors in arteries detect high blood pressure. eneral G “ Rest and digest”: promotes “ Fight or flight”: prepares body for ○ Afferent Pathway: Signal sent to medulla oblongata. Functions energy conservation action ○ Efferent Pathway: Vagus nerve (PSNS) reduces heartrate. ○ Effector: Heart rate slows, lowering blood pressure. Phasic Receptors: Adapt quickly; detect changes. ○ Example: Smell, pressure. tudy Guide: Chapter 16 – Sensory S Tonic Receptors: Adapt slowly; continue signaling. ○ Example: Pain receptors, muscle spindles. Physiology Textbook Reference:Saladin Anatomy and Physiology,10th edition 5. Factors Affecting Sensory Perception Attention, experience, emotion, receptor sensitivity, stimulus strength, and context. 1. Sensory Receptors vs. Sensory Organs Sensory Receptors: Specialized cells or nerve endingsthat detect specific stimuli. 6. General vs. Special Senses ○ Examples: Thermoreceptors (temperature), photoreceptors(light), nociceptors (pain). G eneral Senses: Widely distributed; detect touch,pressure, pain, temperature, Sensory Organs: Structures composed of sensory receptorsand other tissues (e.g., proprioception. connective tissue) that enhance detection of stimuli. ○ Examples: Tactile receptors, nociceptors. ○ Examples: Eyes, ears, taste buds. Special Senses: Localized in specific organs; detectvision, hearing, equilibrium, taste, smell. ○ Examples: Eyes, ears, taste buds. 2. Sensory Information: Four Types T ype: Identifies the nature of the stimulus (e.g.,heat, light, pressure). 7. Sensory Receptor Types and Special Senses Location: Determined by which receptive field is stimulated. Intensity: Encoded by: Receptor Type Stimulus Special Sense ○ Number of receptors activated. ○ Frequency of action potentials. Thermoreceptors emperature T N/A Duration: How long the stimulus lasts. changes Photoreceptors Light Vision Nociceptors Pain N/A 3. Receptive Field and Touch Discrimination echanoreceptor M Pressure, vibration Hearing, equilibrium R eceptive Field: Area monitored by a single sensoryreceptor. s Touch Discrimination: The ability to distinguish betweentwo points of touch. ○ Smaller receptive fields→ Greater touch discrimination(e.g., fingertips). Chemoreceptors Chemicals Taste, smell ○ Larger receptive fields→ Lower discrimination (e.g.,back). 8. Receptors for General Senses 4. Sensory Adaptation and Receptor Types T actile Corpuscles: Light touch. Lamellar (Pacinian) Corpuscles: Deep pressure, vibration. Sensory Adaptation: Reduced sensitivity to a constant stimulus. Muscle Spindles: Muscle stretch. End Bulbs: Light touch, texture. 14. Three Regions of the Ear and Their Function O uter Ear: Collects sound waves. Middle Ear: Amplifies sound vibrations (ossicles). 9. Pain and Referred Pain Inner Ear: Converts vibrations to neural signals (hearing)and detects balance. Pain: Detected by nociceptors. ○ Fast Pain: Sharp, localized (A-delta fibers). ○ Slow Pain: Dull, diffuse (C fibers). 15. Cochlea, Vestibule, and Semicircular Canals Referred Pain: Pain felt in a location distant fromits origin due to shared nerve pathways. C ochlea: Converts sound to nerve signals. ○ Example: Heart attack pain in the left arm. Vestibule: Detects static equilibrium. Semicircular Canals: Detect dynamic equilibrium. 10. Pain Modulation 16. Events of Hearing and Equilibrium E ndogenous opioids (e.g., enkephalins, endorphins) block pain transmission. Gate Control Theory: Non-painful stimuli close “gates”to block pain signals. H earing: Sound waves → Tympanic membrane → Ossicles→ Cochlea → Hair cells → Nerve signals. Equilibrium: Movement of endolymph in vestibular apparatus→ Activates hair cells. 11. Primary Taste Sensations and Influences Five Tastes: Sweet, salty, sour, bitter, umami. 17. Pitch and Loudness Influences: Smell, texture, temperature, genetics,mental state. P itch: Determined by frequency. Loudness: Determined by amplitude. 12. Olfactory Receptors and Perception of Smell Location: Olfactory epithelium in the nasal cavity. 18. Static vs. Dynamic Equilibrium Influences: Age, adaptation, exposure, concentration. S tatic: Perception of head orientation when stationary. Dynamic: Perception of motion or acceleration. 13. Physiology of Taste and Smell G ustation: Chemicals dissolve in saliva → Activatetaste buds → Cranial nerves (VII, 19. Accessory Structures of the Eye IX, X) → Brain. Olfaction: Odorants bind to olfactory receptors → Cranial nerve I → Olfactory bulb → E xamples: Eyelids, eyelashes, eyebrows, lacrimal glands. Brain. Functions: Protect, lubricate, and clean the eye. 20. Anatomy of the Eye and Functions ornea: Refracts light. C 26. Color Vision Lens: Adjusts focus. Retina: Photoreception. D ifferential activation of thethree photopsins(red,green, blue) leads to color Iris: Regulates light entry. perception. 21. Eye Disorders 27. Visual Pathway C ataracts: Clouding of the lens. Retina → Optic Nerve → Optic Chiasm → Optic Tract → Occipital Lobe. Glaucoma: Increased intraocular pressure damages theoptic nerve. Macular Degeneration: Damage to macula; central visionloss. 28. Effects of Visual Pathway Damage 22. Image Formation: Refraction and Accommodation O ptic Nerve: Total blindness in one eye. Optic Chiasm: Loss of peripheral vision (bitemporalhemianopia). R efraction: Bending of light by cornea and lens. Optic Tract: Loss of vision in one visual field (homonymoushemianopia). Accommodation: Lens changes shape to focus on nearor distant objects. 23. Hyperopia vs. Myopia Condition Focus Location Correction tudy Guide: Chapter 17 – The Endocrine S Hyperopia Behind the retina Convex lens System Myopia In front of the retina C oncave lens Textbook Reference:Saladin Anatomy and Physiology,10th edition 24. Fovea Centralis and Optic Disc 1. Compare and Contrast the Nervous and Endocrine Systems F ovea Centralis: Area of sharpest vision (high concentrationof cones). Optic Disc: “Blind spot”; no photoreceptors. Feature Nervous System Endocrine System 25. Rods vs. Cones Communication lectrical signals (action E Hormones in the bloodstream potentials) R ods: Detect dim light; black/white vision. Cones: Detect bright light; color vision. Receptor Properties: Speed Rapid (milliseconds) Slower (seconds to days) ○ Specific to the hormone. ○ Located on theplasma membrane(water-soluble hormones)or inside the cell (lipid-soluble hormones). uration of D Short-lived Long-lasting Effects 5. Chemical Classes of Hormones Target Specific (muscles, glands) idespread (any cell with W Class Composition Solubility Examples receptors) Peptides Amino acid chains Water-soluble Insulin, oxytocin Mode of Action Neurotransmitters at synapses ormones through blood H circulation Steroids erived from D Lipid-soluble Cortisol, testosterone cholesterol 2. Endocrine vs. Exocrine Glands onoamine Modified amino acids M ost are M pinephrine, thyroid E Endocrine Glands: Release hormones into thebloodstream;no ducts. s water-soluble hormone ○ Example: Thyroid, adrenal glands. Exocrine Glands: Release products (e.g., enzymes,sweat) intoductsthat lead to body surfaces or cavities. ○ Example: Sweat glands, salivary glands. 6. Hormone Interaction with Target Cells Lipid-Soluble Hormones(e.g., steroids): 3. Hormones, Paracrine Messengers, and Autocrine Messengers ○ Diffuse through the plasma membrane → Bind tointracellularreceptors→ Activate genes → Protein synthesis. H ormones: Long-distance chemical signals transportedthrough the bloodstream to Water-Soluble Hormones(e.g., peptides): target cells. ○ Bind toreceptors on the plasma membrane→ Activatesecond messenger Paracrine Messengers: Local signals that act on neighboringcells. systems (e.g., cAMP) → Trigger intracellular changes. ○ Example: Histamine. Autocrine Messengers: Signals that act on the samecell that produced them. ○ Example: Interleukins in immune responses. 7. Hypothalamus and Pituitary Glands H ypothalamus: Controls the endocrine system throughhormone secretion. 4. Hormonal Specificity and Receptors Anterior Pituitary: Connected via thehypophyseal portal system; secretes hormones in response to releasing/inhibiting hormones. H ormones circulate throughout the bloodstream but only affecttarget cellswith specific Posterior Pituitary: Connected vianeural connections;stores and releases oxytocin receptors. and ADH (produced by the hypothalamus). Goiter: Enlarged thyroid due to iodine deficiencyor excess TSH stimulation. 8. Location, Anatomy, and Hormones of Endocrine Glands nterior Pituitary: Base of the brain; releases GH,TSH, ACTH, FSH, LH, PRL. A 13. Hypo- and Hypersecretion of Thyroid and Adrenal Hormones Posterior Pituitary: Base of the brain; releases ADH,oxytocin. Thyroid Gland: Neck; releases T3, T4, calcitonin. Thyroid Hormone: Parathyroid Glands: On thyroid; release PTH. ○ Hyposecretion: Weight gain, fatigue, slow metabolism(hypothyroidism). Pancreas: Abdominal cavity; releases insulin, glucagon. ○ Hypersecretion: Weight loss, nervousness, increasedmetabolism Adrenal Glands: On kidneys; release cortisol, aldosterone,epinephrine, (hyperthyroidism). norepinephrine. Adrenal Hormones: Gonads: Ovaries (estrogen, progesterone), testes (testosterone). ○ Hyposecretion: Addison's disease (low cortisol). ○ Hypersecretion: Cushing's syndrome (high cortisol). 9. Physiological Effects and Feedback Pathways 14. Type 1 and Type 2 Diabetes Mellitus Example (Thyroid Hormone): ○ Hypothalamus → TRH → Anterior Pituitary → TSH → Thyroid → T3/T4 → Type 1 Diabetes: Increases metabolism. ○ Cause: Autoimmune destruction of beta cells → No insulin production. ○ Negative Feedback: High T3/T4 inhibits TRH and TSH. ○ Symptoms: High blood glucose, polyuria, weight loss. Type 2 Diabetes: ○ Cause: Insulin resistance (cells don’t respond to insulin). ○ Symptoms: Similar to Type 1 but develops gradually. 10. Negative Feedback in Hormonal Regulation Negative feedback ensures hormonal levels stay within a narrow range. ○ Example: Blood glucose levels – Insulin lowers blood glucose, glucagon raises it. 11. Hormone Classification S teroids: Lipid-soluble; derived from cholesterol. Peptides: Amino acid-based; water-soluble. Monoamines: Derived from amino acids; include catecholamines(e.g., epinephrine) and thyroid hormone. 12. Gigantism, Acromegaly, Dwarfism, and Goiter G igantism: Excess growth hormone (GH)beforegrowthplates close. Acromegaly: Excess GHaftergrowth plates close. Dwarfism: GH deficiency during childhood.
