Results for "ATPase"

ATPase

# Synaptic transmission and the vesicle cycle ILO: - the two fundamental synaptic mechanisms by which excitable cells and in particular neurones can affect one another's function: electrical or chemical synaptic communication - how a neurotransmitter supporting chemical synaptic communication is defined and the diversity of types of small molecules that can be defined as being a neurotransmitter - how these are stored in small membranous vesicles, what constitutes the classical vesicle cycle and full collapse vesicle fusion during release - the experimental evidence for this full collapse fusion release model and how the vesicle membrane is recycled - further experimental evidence for an alternative to this model: the "kiss and run" model of vesicle cycling - the proteins that make up the release machinery and how they are readied for release during "docking" and "priming" - what happens to these proteins during the release process and the subsequent retrieval of vesicle membrane following full collapse fusion # Types of synapse - **chemical synapse** - molecules stored in vesicles - molecules diffuse across a gap - relatively slow - unidirectional - majority of synaptic transmission in the nervous system - **electrical synapse** - holes in adjoining cell membranes - linked by channels - gap junctions or connexons - signalling is very fast - bidirectional - direct electrical coupling between cells - electrical synchronisation in the heart - relatively rare in the nervous system - inhibitory interneurons or local networks # Chemical synapse Key functional roles - Neural computation - integration of many input +/- - Exhibit plasticity - development, learning and memory - Act as targets for drug action - neurotransmitter synthesis, release, receptors, uptake, degradation to produce a broad range or complex series of effects - inc functional flexibility ## Neurotransmitter 6 criteria :  ### Types  - amino acids - amines - purines - peptides - **dales principle** - neurons release just one transmitter at all of its synapses - how is dales principle challenged? - challenged by co existence and co release of small molecule transmitter and peptides by interneurons eg GABA and enkephalins - and more than one small molecule transmitter in some projection pathways eg L glutamate and dopamine ## Vesicles - neurotransmitters are likely to be stored in one type of vesicle ### Types  For LDCVs - concentration is lower because of the relatively proximity to the voltage gated channels - only seen when there is sustained AP in a more global manner rather than restricted to synaptic active zone ### Cycling  1. vesicle is filled with neurotransmitter with appropriate transporter which uses ATP as an energy source to drive against conc gradient and fill the vesicle 2. vesicle collected in to reserve pool, mobilised to active zone for docking 1. atp dependent process 3. primed to be sensitive to calc conc to initiate membrane fusion 1. also atp dependent 4. exocytosis following inc in intracellular conc of calcium 5. vesicle membrane fully collapses into the membrane 6. loss of membrane recovered with endocytosis, calcium dependent with coated pits 1. uncoating requires atp 7. small vesicles become part of endosome, all recycled 8. then pinched off again to start the cycle ### Evidence for full fusion/collapse - slam freezing - rapidly cooling of the neuromuscular junction on a metal block after electrical stimulation of motor neurone axon fibres to initiate acetylcholine release - sections of the presynaptic membrane were visualised at different types after electrical stimulation to follow any changes in presynaptic membrane - activity led to increase in membrane surface area - therefore vesicle recycling ### Step 1 - docking - close association with plasma membrane - synaptic vesicles only dock at active zone - presynaptic area adjacent to signal transduction machinery - active zones differ between neurons by vesicle number ### Step 2 - priming - ready for release - maturation of synaptic vesicle - made competent to release transmitter - requires ATP - conformational change in proteins that drive release ### Step 3 fusion/exocytosis - full fusion of synaptic vesicle and presynaptic terminal membrane - requires calcium - calcium sensor protein - fusion induces exocytosis - takes 1ms ### Step 4 endocytosis - recovery of fused membrane - triggered by inc intracellular calcium - involves cytoskeletal protein lattice formation from clathrin monomers - this helps to pinch off membrane with clathrin coated pits - takes about 5 seconds - ATP dependent ### Step 5 - recycling - mechanism to conserve synaptic vesicle membrane via endosome - decoating of clathrin coated pits is also atp dependent - vesicles refill with transmitter - atp dependent ### Kiss and Run Model? - fast recycling and low capacity, favoured at low frequency stimulation - may be majority of glutamate release in hippocampus - whereas classical is slow, high capacity, favoured at high frequency stimulation - full vesicle fusion may not be required - neurotransmitter leaks out of small fusion pores - SSVs recycled intact - and not recycled as clathrin coated vesicles via the endosome Functional evidence - flickering capacitance changes instead of up stepping capacitance - capacitance dependent on surface area ### Targeting vesicles Vesicle associated proteins - synaptobrevins VAMP - synaptotagmins Plasma membrane associated proteins - SNAP-25 - syntaxins ### Snares for release - synaptobrevin - single transmembrane spanning - t snare - syntaxin - single transmembrane spanning - SNAP-25 - anchored to membrane by S-acylation ### Release machinery in the different steps     Syntaxin regulatory domain is important in maintaining a tight connection to the cell membrane Snares form a tighter complex during priming - atp dependent - Habc domains binding assisted by Munc18 - zippering - formation of the SNARE pins What is the Ca2+ sensor? - synaptotagmin - found on vesciles - binds to SNARE pins in absence of Ca2+ - during priming - binds to phospholipids in C region in presence of Ca2+ - Ca2+ binding may cause synaptotagmin to pull vesicle into membrane Why must SNAREs disassociate? - to allow internalisation of empty vesicles - re docking of another vesicle - involves NSF - ATPase which binds to the SNARE-pin complex to facilitate disassociation

BIOC 503 - MEMBRANE TRANSPORT

NEUS 609 - Neurotransmitters & their Receptors

Endocrine System 1. What are hormones and what is their function in the body? Hormones are chemical messengers transported in the bloodstream that stimulate physiological responses in target cells or organs. 2. Types of hormones Endocrine System 1. What are hormones and what is their function in the body? Hormones are chemical messengers transported in the bloodstream that stimulate physiological responses in target cells or organs. 2. Types of hormones based on chemical composition and how they enter target cells: • Steroid hormones: Lipid-soluble, diffuse through cell membrane (e.g., cortisol). • Protein/Peptide hormones: Water-soluble, bind to surface receptors (e.g., insulin). • Biogenic/Monoamines: Derived from amino acids (e.g., T3/T4), may need carriers or membrane receptors. 3. Know all 6 hormones secreted by the anterior pituitary gland and their functions: • TSH: Stimulates thyroid to release T3 and T4. • ACTH: Stimulates adrenal cortex to release cortisol. • GH: Stimulates tissue growth and protein synthesis. • PRL: Stimulates milk production. • FSH: Stimulates egg maturation/sperm production. • LH: Triggers ovulation and testosterone production. 4. What is thymosin? Which gland secretes it? What is its function? Thymosin is secreted by the thymus and helps in the development and maturation of T-cells. 5. Know thyroid gland hormones, the cells that secrete them, and their functions: • T3 & T4 (follicular cells): Increase metabolism and regulate appetite. • Calcitonin (C cells): Lowers blood calcium levels. 6. Know the hormones secreted by the adrenal gland and their specific functions: • Cortex: • Aldosterone: Retains Na⁺, excretes K⁺, raises blood pressure. • Cortisol: Increases glucose, metabolism of fat/protein. • Androgens: Precursor to sex hormones. • Medulla: • Epinephrine/Norepinephrine: Increase heart rate, blood flow, and alertness. 7. Function of glucagon and insulin in maintaining homeostasis: • Insulin (beta cells): Lowers blood glucose. • Glucagon (alpha cells): Raises blood glucose. • Antagonistic: They have opposing effects to balance blood sugar levels. 8. Which cells are involved in spermatogenesis? Where does sperm production occur? • Sertoli (Sustentacular) cells support spermatogenesis. • Leydig (Interstitial) cells produce testosterone. • Occurs in the seminiferous tubules of the testes. 9. Know the hormones secreted by the testes and their functions: • Testosterone: Stimulates male development and sperm production. • Inhibin: Inhibits FSH to regulate sperm production. 10. What causes diabetes insipidus? How is it different from diabetes mellitus? • Diabetes insipidus: ADH deficiency → excessive urination. • Diabetes mellitus: Insulin issues → high blood glucose. 11. Know the 3 “P’s” of diabetes: • Polyuria: Excessive urination. • Polydipsia: Excessive thirst. • Polyphagia: Excessive hunger. 12. How are oxytocin and prolactin different? • Oxytocin: Stimulates uterine contractions and milk letdown. • Prolactin: Stimulates milk production. 13. Name the ovarian hormones and their functions: • Estrogen/Progesterone: Regulate cycle, pregnancy, and secondary sex characteristics. • Inhibin: Inhibits FSH secretion. ⸻ Muscle Physiology 14. Know 3 muscle types, their locations, and function: • Skeletal: Attached to bones; movement; voluntary. • Cardiac: Heart; pumps blood; involuntary. • Smooth: Organs/vessels; propels substances; involuntary. 15. Know the layers surrounding muscle: • Epimysium: Surrounds entire muscle. • Perimysium: Surrounds fascicle (bundle). • Endomysium: Surrounds individual fiber. 16. What is a fascicle? A bundle of muscle fibers. 17. What is a sarcomere? Name its regions: Smallest contractile unit (Z-disc to Z-disc). • Z-band, A-band (dark), I-band (light), H-zone. 18. What are actin and myosin? • Actin: Thin filament. • Myosin: Thick filament that pulls actin during contraction. 19. What is troponin and tropomyosin? • Tropomyosin blocks binding sites on actin. • Troponin binds Ca²⁺ to move tropomyosin and expose sites. 20. What is a motor unit? A motor neuron and all muscle fibers it controls. 21. Role of T-Tubule, SR, Terminal Cisternae: • T-Tubule: Conducts AP into cell. • SR: Stores calcium. • Terminal cisternae: Release calcium. 22. Which neurotransmitter is released at the neuromuscular junction? Acetylcholine (ACh). 23. What role does Ca²⁺ play in muscle physiology? Binds troponin, moves tropomyosin, exposes actin sites. 24. What happens to Ca²⁺ after action potential ends? Reabsorbed into SR by Ca²⁺ ATPase pump. 25. What is the function of ATP in muscle physiology? Powers myosin movement, detachment, and Ca²⁺ reuptake. 26. What is sliding filament theory? Myosin pulls actin filaments → sarcomere shortens → contraction. 27. What are DHP and Ryanodine receptors and their roles? • DHP: Voltage sensor in T-tubule. • Ryanodine: Releases Ca²⁺ from SR. 28. What is the function of AChE? Breaks down ACh to stop stimulation and contraction. 29. Difference between isotonic and isometric contractions: • Isotonic: Muscle changes length (shortens/lengthens). • Isometric: Muscle length stays same; tension builds. ⸻ Respiratory Physiology 30. Difference between conductive and respiratory divisions: • Conductive: Air passageways (nose to bronchioles). • Respiratory: Gas exchange (alveoli). 31. Type I & II alveolar cells and functions: • Type I: Gas exchange. • Type II: Secretes surfactant, repairs alveoli. 32. Dust cells and their functions: Alveolar macrophages that clean up particles/debris. 33. Muscles in relaxed vs. forced respiration: • Relaxed inhale: Diaphragm, external intercostals. • Forced inhale: Accessory neck muscles. • Forced exhale: Internal intercostals, abdominals. 34. What happens to pressure and volume when inhaling/exhaling? • Inhale: Volume ↑, pressure ↓. • Exhale: Volume ↓, pressure ↑. 35. Difference between systemic and pulmonary exchange: • Systemic: Gas exchange at tissues. • Pulmonary: Gas exchange in lungs. 36. What cells are involved in carrying gases? Red blood cells (RBCs). 37. Which enzyme converts CO₂ + H₂O → H₂CO₃? Carbonic anhydrase. 38. What does carbonic acid break into? H⁺ + HCO₃⁻ (bicarbonate ion). 39. What happens in hypoxia (low oxygen)? • ↓O₂, ↑CO₂, ↓pH (acidosis). 40. What happens in hypercapnia (high CO₂)? • ↑CO₂, ↓O₂, ↓pH (acidosis). 41. Receptors for blood pH and their locations: • Central (CSF pH): Medulla oblongata. • Peripheral (O₂, CO₂, pH): Carotid & aortic bodies. 42. CO₂ loading & O₂ unloading at tissues: • CO₂ enters blood → forms HCO₃⁻. • O₂ released to tissues. 43. CO₂ unloading & O₂ loading at alveoli: • CO₂ released from blood to lungs. • O₂ binds to hemoglobin. 44. Brain part for unconscious breathing: Medulla oblongata. 45. Obstructive vs. restrictive disorders + example: • Obstructive: Narrowed airways (asthma). • Restrictive: Reduced lung expansion (fibrosis). 46. Know spirometry volumes (not numbers): • Tidal volume, • Inspiratory/Expiratory reserve volume, • Residual volume, • Vital capacity, • Total lung capacity, • Inspiratory capacity, • Functional residual capacity. 47. Define eupnea, dyspnea, tachypnea, apnea, Kussmaul respiration: • Eupnea: Normal breathing. • Dyspnea: Labored breathing. • Tachypnea: Rapid, shallow breathing. • Apnea: No breathing. • Kussmaul: Deep, rapid (from acidosis Endocrine System 1. What are hormones and what is their function in the body? Hormones are chemical messengers transported in the bloodstream that stimulate physiological responses in target cells or organs. 2. Types of hormones based on chemical composition and how they enter target cells: • Steroid hormones: Lipid-soluble, diffuse through cell membrane (e.g., cortisol). • Protein/Peptide hormones: Water-soluble, bind to surface receptors (e.g., insulin). • Biogenic/Monoamines: Derived from amino acids (e.g., T3/T4), may need carriers or membrane receptors. 3. Know all 6 hormones secreted by the anterior pituitary gland and their functions: • TSH: Stimulates thyroid to release T3 and T4. • ACTH: Stimulates adrenal cortex to release cortisol. • GH: Stimulates tissue growth and protein synthesis. • PRL: Stimulates milk production. • FSH: Stimulates egg maturation/sperm production. • LH: Triggers ovulation and testosterone production. 4. What is thymosin? Which gland secretes it? What is its function? Thymosin is secreted by the thymus and helps in the development and maturation of T-cells. 5. Know thyroid gland hormones, the cells that secrete them, and their functions: • T3 & T4 (follicular cells): Increase metabolism and regulate appetite. • Calcitonin (C cells): Lowers blood calcium levels. 6. Know the hormones secreted by the adrenal gland and their specific functions: • Cortex: • Aldosterone: Retains Na⁺, excretes K⁺, raises blood pressure. • Cortisol: Increases glucose, metabolism of fat/protein. • Androgens: Precursor to sex hormones. • Medulla: • Epinephrine/Norepinephrine: Increase heart rate, blood flow, and alertness. 7. Function of glucagon and insulin in maintaining homeostasis: • Insulin (beta cells): Lowers blood glucose. • Glucagon (alpha cells): Raises blood glucose. • Antagonistic: They have opposing effects to balance blood sugar levels. 8. Which cells are involved in spermatogenesis? Where does sperm production occur? • Sertoli (Sustentacular) cells support spermatogenesis. • Leydig (Interstitial) cells produce testosterone. • Occurs in the seminiferous tubules of the testes. 9. Know the hormones secreted by the testes and their functions: • Testosterone: Stimulates male development and sperm production. • Inhibin: Inhibits FSH to regulate sperm production. 10. What causes diabetes insipidus? How is it different from diabetes mellitus? • Diabetes insipidus: ADH deficiency → excessive urination. • Diabetes mellitus: Insulin issues → high blood glucose. 11. Know the 3 “P’s” of diabetes: • Polyuria: Excessive urination. • Polydipsia: Excessive thirst. • Polyphagia: Excessive hunger. 12. How are oxytocin and prolactin different? • Oxytocin: Stimulates uterine contractions and milk letdown. • Prolactin: Stimulates milk production. 13. Name the ovarian hormones and their functions: • Estrogen/Progesterone: Regulate cycle, pregnancy, and secondary sex characteristics. • Inhibin: Inhibits FSH secretion. ⸻ Muscle Physiology 14. Know 3 muscle types, their locations, and function: • Skeletal: Attached to bones; movement; voluntary. • Cardiac: Heart; pumps blood; involuntary. • Smooth: Organs/vessels; propels substances; involuntary. 15. Know the layers surrounding muscle: • Epimysium: Surrounds entire muscle. • Perimysium: Surrounds fascicle (bundle). • Endomysium: Surrounds individual fiber. 16. What is a fascicle? A bundle of muscle fibers. 17. What is a sarcomere? Name its regions: Smallest contractile unit (Z-disc to Z-disc). • Z-band, A-band (dark), I-band (light), H-zone. 18. What are actin and myosin? • Actin: Thin filament. • Myosin: Thick filament that pulls actin during contraction. 19. What is troponin and tropomyosin? • Tropomyosin blocks binding sites on actin. • Troponin binds Ca²⁺ to move tropomyosin and expose sites. 20. What is a motor unit? A motor neuron and all muscle fibers it controls. 21. Role of T-Tubule, SR, Terminal Cisternae: • T-Tubule: Conducts AP into cell. • SR: Stores calcium. • Terminal cisternae: Release calcium. 22. Which neurotransmitter is released at the neuromuscular junction? Acetylcholine (ACh). 23. What role does Ca²⁺ play in muscle physiology? Binds troponin, moves tropomyosin, exposes actin sites. 24. What happens to Ca²⁺ after action potential ends? Reabsorbed into SR by Ca²⁺ ATPase pump. 25. What is the function of ATP in muscle physiology? Powers myosin movement, detachment, and Ca²⁺ reuptake. 26. What is sliding filament theory? Myosin pulls actin filaments → sarcomere shortens → contraction. 27. What are DHP and Ryanodine receptors and their roles? • DHP: Voltage sensor in T-tubule. • Ryanodine: Releases Ca²⁺ from SR. 28. What is the function of AChE? Breaks down ACh to stop stimulation and contraction. 29. Difference between isotonic and isometric contractions: • Isotonic: Muscle changes length (shortens/lengthens). • Isometric: Muscle length stays same; tension builds. ⸻ Respiratory Physiology 30. Difference between conductive and respiratory divisions: • Conductive: Air passageways (nose to bronchioles). • Respiratory: Gas exchange (alveoli). 31. Type I & II alveolar cells and functions: • Type I: Gas exchange. • Type II: Secretes surfactant, repairs alveoli. 32. Dust cells and their functions: Alveolar macrophages that clean up particles/debris. 33. Muscles in relaxed vs. forced respiration: • Relaxed inhale: Diaphragm, external intercostals. • Forced inhale: Accessory neck muscles. • Forced exhale: Internal intercostals, abdominals. 34. What happens to pressure and volume when inhaling/exhaling? • Inhale: Volume ↑, pressure ↓. • Exhale: Volume ↓, pressure ↑. 35. Difference between systemic and pulmonary exchange: • Systemic: Gas exchange at tissues. • Pulmonary: Gas exchange in lungs. 36. What cells are involved in carrying gases? Red blood cells (RBCs). 37. Which enzyme converts CO₂ + H₂O → H₂CO₃? Carbonic anhydrase. 38. What does carbonic acid break into? H⁺ + HCO₃⁻ (bicarbonate ion). 39. What happens in hypoxia (low oxygen)? • ↓O₂, ↑CO₂, ↓pH (acidosis). 40. What happens in hypercapnia (high CO₂)? • ↑CO₂, ↓O₂, ↓pH (acidosis). 41. Receptors for blood pH and their locations: • Central (CSF pH): Medulla oblongata. • Peripheral (O₂, CO₂, pH): Carotid & aortic bodies. 42. CO₂ loading & O₂ unloading at tissues: • CO₂ enters blood → forms HCO₃⁻. • O₂ released to tissues. 43. CO₂ unloading & O₂ loading at alveoli: • CO₂ released from blood to lungs. • O₂ binds to hemoglobin. 44. Brain part for unconscious breathing: Medulla oblongata. 45. Obstructive vs. restrictive disorders + example: • Obstructive: Narrowed airways (asthma). • Restrictive: Reduced lung expansion (fibrosis). 46. Know spirometry volumes (not numbers): • Tidal volume, • Inspiratory/Expiratory reserve volume, • Residual volume, • Vital capacity, • Total lung capacity, • Inspiratory capacity, • Functional residual capacity. 47. Define eupnea, dyspnea, tachypnea, apnea, Kussmaul respiration: • Eupnea: Normal breathing. • Dyspnea: Labored breathing. • Tachypnea: Rapid, shallow breathing. • Apnea: No breathing. • Kussmaul: Deep, rapid (from acidosis Endocrine System 1. What are hormones and what is their function in the body? Hormones are chemical messengers transported in the bloodstream that stimulate physiological responses in target cells or organs. 2. Types of hormones based on chemical composition and how they enter target cells: • Steroid hormones: Lipid-soluble, diffuse through cell membrane (e.g., cortisol). • Protein/Peptide hormones: Water-soluble, bind to surface receptors (e.g., insulin). • Biogenic/Monoamines: Derived from amino acids (e.g., T3/T4), may need carriers or membrane receptors. 3. Know all 6 hormones secreted by the anterior pituitary gland and their functions: • TSH: Stimulates thyroid to release T3 and T4. • ACTH: Stimulates adrenal cortex to release cortisol. • GH: Stimulates tissue growth and protein synthesis. • PRL: Stimulates milk production. • FSH: Stimulates egg maturation/sperm production. • LH: Triggers ovulation and testosterone production. 4. What is thymosin? Which gland secretes it? What is its function? Thymosin is secreted by the thymus and helps in the development and maturation of T-cells. 5. Know thyroid gland hormones, the cells that secrete them, and their functions: • T3 & T4 (follicular cells): Increase metabolism and regulate appetite. • Calcitonin (C cells): Lowers blood calcium levels. 6. Know the hormones secreted by the adrenal gland and their specific functions: • Cortex: • Aldosterone: Retains Na⁺, excretes K⁺, raises blood pressure. • Cortisol: Increases glucose, metabolism of fat/protein. • Androgens: Precursor to sex hormones. • Medulla: • Epinephrine/Norepinephrine: Increase heart rate, blood flow, and alertness. 7. Function of glucagon and insulin in maintaining homeostasis: • Insulin (beta cells): Lowers blood glucose. • Glucagon (alpha cells): Raises blood glucose. • Antagonistic: They have opposing effects to balance blood sugar levels. 8. Which cells are involved in spermatogenesis? Where does sperm production occur? • Sertoli (Sustentacular) cells support spermatogenesis. • Leydig (Interstitial) cells produce testosterone. • Occurs in the seminiferous tubules of the testes. 9. Know the hormones secreted by the testes and their functions: • Testosterone: Stimulates male development and sperm production. • Inhibin: Inhibits FSH to regulate sperm production. 10. What causes diabetes insipidus? How is it different from diabetes mellitus? • Diabetes insipidus: ADH deficiency → excessive urination. • Diabetes mellitus: Insulin issues → high blood glucose. 11. Know the 3 “P’s” of diabetes: • Polyuria: Excessive urination. • Polydipsia: Excessive thirst. • Polyphagia: Excessive hunger. 12. How are oxytocin and prolactin different? • Oxytocin: Stimulates uterine contractions and milk letdown. • Prolactin: Stimulates milk production. 13. Name the ovarian hormones and their functions: • Estrogen/Progesterone: Regulate cycle, pregnancy, and secondary sex characteristics. • Inhibin: Inhibits FSH secretion. ⸻ Muscle Physiology 14. Know 3 muscle types, their locations, and function: • Skeletal: Attached to bones; movement; voluntary. • Cardiac: Heart; pumps blood; involuntary. • Smooth: Organs/vessels; propels substances; involuntary. 15. Know the layers surrounding muscle: • Epimysium: Surrounds entire muscle. • Perimysium: Surrounds fascicle (bundle). • Endomysium: Surrounds individual fiber. 16. What is a fascicle? A bundle of muscle fibers. 17. What is a sarcomere? Name its regions: Smallest contractile unit (Z-disc to Z-disc). • Z-band, A-band (dark), I-band (light), H-zone. 18. What are actin and myosin? • Actin: Thin filament. • Myosin: Thick filament that pulls actin during contraction. 19. What is troponin and tropomyosin? • Tropomyosin blocks binding sites on actin. • Troponin binds Ca²⁺ to move tropomyosin and expose sites. 20. What is a motor unit? A motor neuron and all muscle fibers it controls. 21. Role of T-Tubule, SR, Terminal Cisternae: • T-Tubule: Conducts AP into cell. • SR: Stores calcium. • Terminal cisternae: Release calcium. 22. Which neurotransmitter is released at the neuromuscular junction? Acetylcholine (ACh). 23. What role does Ca²⁺ play in muscle physiology? Binds troponin, moves tropomyosin, exposes actin sites. 24. What happens to Ca²⁺ after action potential ends? Reabsorbed into SR by Ca²⁺ ATPase pump. 25. What is the function of ATP in muscle physiology? Powers myosin movement, detachment, and Ca²⁺ reuptake. 26. What is sliding filament theory? Myosin pulls actin filaments → sarcomere shortens → contraction. 27. What are DHP and Ryanodine receptors and their roles? • DHP: Voltage sensor in T-tubule. • Ryanodine: Releases Ca²⁺ from SR. 28. What is the function of AChE? Breaks down ACh to stop stimulation and contraction. 29. Difference between isotonic and isometric contractions: • Isotonic: Muscle changes length (shortens/lengthens). • Isometric: Muscle length stays same; tension builds. ⸻ Respiratory Physiology 30. Difference between conductive and respiratory divisions: • Conductive: Air passageways (nose to bronchioles). • Respiratory: Gas exchange (alveoli). 31. Type I & II alveolar cells and functions: • Type I: Gas exchange. • Type II: Secretes surfactant, repairs alveoli. 32. Dust cells and their functions: Alveolar macrophages that clean up particles/debris. 33. Muscles in relaxed vs. forced respiration: • Relaxed inhale: Diaphragm, external intercostals. • Forced inhale: Accessory neck muscles. • Forced exhale: Internal intercostals, abdominals. 34. What happens to pressure and volume when inhaling/exhaling? • Inhale: Volume ↑, pressure ↓. • Exhale: Volume ↓, pressure ↑. 35. Difference between systemic and pulmonary exchange: • Systemic: Gas exchange at tissues. • Pulmonary: Gas exchange in lungs. 36. What cells are involved in carrying gases? Red blood cells (RBCs). 37. Which enzyme converts CO₂ + H₂O → H₂CO₃? Carbonic anhydrase. 38. What does carbonic acid break into? H⁺ + HCO₃⁻ (bicarbonate ion). 39. What happens in hypoxia (low oxygen)? • ↓O₂, ↑CO₂, ↓pH (acidosis). 40. What happens in hypercapnia (high CO₂)? • ↑CO₂, ↓O₂, ↓pH (acidosis). 41. Receptors for blood pH and their locations: • Central (CSF pH): Medulla oblongata. • Peripheral (O₂, CO₂, pH): Carotid & aortic bodies. 42. CO₂ loading & O₂ unloading at tissues: • CO₂ enters blood → forms HCO₃⁻. • O₂ released to tissues. 43. CO₂ unloading & O₂ loading at alveoli: • CO₂ released from blood to lungs. • O₂ binds to hemoglobin. 44. Brain part for unconscious breathing: Medulla oblongata. 45. Obstructive vs. restrictive disorders + example: • Obstructive: Narrowed airways (asthma). • Restrictive: Reduced lung expansion (fibrosis). 46. Know spirometry volumes (not numbers): • Tidal volume, • Inspiratory/Expiratory reserve volume, • Residual volume, • Vital capacity, • Total lung capacity, • Inspiratory capacity, • Functional residual capacity. 47. Define eupnea, dyspnea, tachypnea, apnea, Kussmaul respiration: • Eupnea: Normal breathing. • Dyspnea: Labored breathing. • Tachypnea: Rapid, shallow breathing. • Apnea: No breathing. • Kussmaul: Deep, rapid (from acidosis based on chemical composition and how they enter target cells: • Steroid hormones: Lipid-soluble, diffuse through cell membrane (e.g., cortisol). • Protein/Peptide hormones: Water-soluble, bind to surface receptors (e.g., insulin). • Biogenic/Monoamines: Derived from amino acids (e.g., T3/T4), may need carriers or membrane receptors. 3. Know all 6 hormones secreted by the anterior pituitary gland and their functions: • TSH: Stimulates thyroid to release T3 and T4. • ACTH: Stimulates adrenal cortex to release cortisol. • GH: Stimulates tissue growth and protein synthesis. • PRL: Stimulates milk production. • FSH: Stimulates egg maturation/sperm production. • LH: Triggers ovulation and testosterone production. 4. What is thymosin? Which gland secretes it? What is its function? Thymosin is secreted by the thymus and helps in the development and maturation of T-cells. 5. Know thyroid gland hormones, the cells that secrete them, and their functions: • T3 & T4 (follicular cells): Increase metabolism and regulate appetite. • Calcitonin (C cells): Lowers blood calcium levels. 6. Know the hormones secreted by the adrenal gland and their specific functions: • Cortex: • Aldosterone: Retains Na⁺, excretes K⁺, raises blood pressure. • Cortisol: Increases glucose, metabolism of fat/protein. • Androgens: Precursor to sex hormones. • Medulla: • Epinephrine/Norepinephrine: Increase heart rate, blood flow, and alertness. 7. Function of glucagon and insulin in maintaining homeostasis: • Insulin (beta cells): Lowers blood glucose. • Glucagon (alpha cells): Raises blood glucose. • Antagonistic: They have opposing effects to balance blood sugar levels. 8. Which cells are involved in spermatogenesis? Where does sperm production occur? • Sertoli (Sustentacular) cells support spermatogenesis. • Leydig (Interstitial) cells produce testosterone. • Occurs in the seminiferous tubules of the testes. 9. Know the hormones secreted by the testes and their functions: • Testosterone: Stimulates male development and sperm production. • Inhibin: Inhibits FSH to regulate sperm production. 10. What causes diabetes insipidus? How is it different from diabetes mellitus? • Diabetes insipidus: ADH deficiency → excessive urination. • Diabetes mellitus: Insulin issues → high blood glucose. 11. Know the 3 “P’s” of diabetes: • Polyuria: Excessive urination. • Polydipsia: Excessive thirst. • Polyphagia: Excessive hunger. 12. How are oxytocin and prolactin different? • Oxytocin: Stimulates uterine contractions and milk letdown. • Prolactin: Stimulates milk production. 13. Name the ovarian hormones and their functions: • Estrogen/Progesterone: Regulate cycle, pregnancy, and secondary sex characteristics. • Inhibin: Inhibits FSH secretion. ⸻ Muscle Physiology 14. Know 3 muscle types, their locations, and function: • Skeletal: Attached to bones; movement; voluntary. • Cardiac: Heart; pumps blood; involuntary. • Smooth: Organs/vessels; propels substances; involuntary. 15. Know the layers surrounding muscle: • Epimysium: Surrounds entire muscle. • Perimysium: Surrounds fascicle (bundle). • Endomysium: Surrounds individual fiber. 16. What is a fascicle? A bundle of muscle fibers. 17. What is a sarcomere? Name its regions: Smallest contractile unit (Z-disc to Z-disc). • Z-band, A-band (dark), I-band (light), H-zone. 18. What are actin and myosin? • Actin: Thin filament. • Myosin: Thick filament that pulls actin during contraction. 19. What is troponin and tropomyosin? • Tropomyosin blocks binding sites on actin. • Troponin binds Ca²⁺ to move tropomyosin and expose sites. 20. What is a motor unit? A motor neuron and all muscle fibers it controls. 21. Role of T-Tubule, SR, Terminal Cisternae: • T-Tubule: Conducts AP into cell. • SR: Stores calcium. • Terminal cisternae: Release calcium. 22. Which neurotransmitter is released at the neuromuscular junction? Acetylcholine (ACh). 23. What role does Ca²⁺ play in muscle physiology? Binds troponin, moves tropomyosin, exposes actin sites. 24. What happens to Ca²⁺ after action potential ends? Reabsorbed into SR by Ca²⁺ ATPase pump. 25. What is the function of ATP in muscle physiology? Powers myosin movement, detachment, and Ca²⁺ reuptake. 26. What is sliding filament theory? Myosin pulls actin filaments → sarcomere shortens → contraction. 27. What are DHP and Ryanodine receptors and their roles? • DHP: Voltage sensor in T-tubule. • Ryanodine: Releases Ca²⁺ from SR. 28. What is the function of AChE? Breaks down ACh to stop stimulation and contraction. 29. Difference between isotonic and isometric contractions: • Isotonic: Muscle changes length (shortens/lengthens). • Isometric: Muscle length stays same; tension builds. ⸻ Respiratory Physiology 30. Difference between conductive and respiratory divisions: • Conductive: Air passageways (nose to bronchioles). • Respiratory: Gas exchange (alveoli). 31. Type I & II alveolar cells and functions: • Type I: Gas exchange. • Type II: Secretes surfactant, repairs alveoli. 32. Dust cells and their functions: Alveolar macrophages that clean up particles/debris. 33. Muscles in relaxed vs. forced respiration: • Relaxed inhale: Diaphragm, external intercostals. • Forced inhale: Accessory neck muscles. • Forced exhale: Internal intercostals, abdominals. 34. What happens to pressure and volume when inhaling/exhaling? • Inhale: Volume ↑, pressure ↓. • Exhale: Volume ↓, pressure ↑. 35. Difference between systemic and pulmonary exchange: • Systemic: Gas exchange at tissues. • Pulmonary: Gas exchange in lungs. 36. What cells are involved in carrying gases? Red blood cells (RBCs). 37. Which enzyme converts CO₂ + H₂O → H₂CO₃? Carbonic anhydrase. 38. What does carbonic acid break into? H⁺ + HCO₃⁻ (bicarbonate ion). 39. What happens in hypoxia (low oxygen)? • ↓O₂, ↑CO₂, ↓pH (acidosis). 40. What happens in hypercapnia (high CO₂)? • ↑CO₂, ↓O₂, ↓pH (acidosis). 41. Receptors for blood pH and their locations: • Central (CSF pH): Medulla oblongata. • Peripheral (O₂, CO₂, pH): Carotid & aortic bodies. 42. CO₂ loading & O₂ unloading at tissues: • CO₂ enters blood → forms HCO₃⁻. • O₂ released to tissues. 43. CO₂ unloading & O₂ loading at alveoli: • CO₂ released from blood to lungs. • O₂ binds to hemoglobin. 44. Brain part for unconscious breathing: Medulla oblongata. 45. Obstructive vs. restrictive disorders + example: • Obstructive: Narrowed airways (asthma). • Restrictive: Reduced lung expansion (fibrosis). 46. Know spirometry volumes (not numbers): • Tidal volume, • Inspiratory/Expiratory reserve volume, • Residual volume, • Vital capacity, • Total lung capacity, • Inspiratory capacity, • Functional residual capacity. 47. Define eupnea, dyspnea, tachypnea, apnea, Kussmaul respiration: • Eupnea: Normal breathing. • Dyspnea: Labored breathing. • Tachypnea: Rapid, shallow breathing. • Apnea: No breathing

Lecture_7 transport ATPases

Chapter 2: NA+/K +ATPase