TUTORIAL DISCUSSION – 1 PHSL- 215 Dr. Zahoor 1

Topics Lecture 1: Homeostasis Lecture 4: Inter Cellular Communication & Signal Transduction 2

Homeostasis Q.1 What is Physiology? Physiology deals with functions of the body to keep the HOMEOSTASIS Q2. What is Homeostasis? is to keep the INTERNAL- ENVIORNMENT of the cell constant Q3. What are Cell Functions? Basic: Obtaining food and O 2 from the surrounding. Perform chemical reaction to use food and O 2 Food + Oxygen = CO2+ H2O+Energy Eliminate CO2 and other waste products. Synthesize protein. Exchange of material through cell membrane Specialized: Digestive System - secrete digestive enzymes Muscle Cells - Muscle contraction Nerve Cell - send electrical impulses 3

Q4. Name 4 types of tissues. 1- Muscle Tissue 2- Nervous Tissue 3- Epithelial Tissue 4- Connective Tissue Q5. What is function of Cardiac Muscle? To pump out the blood Q6. What is difference between central and peripheral neurons system? 4 centralperipheral BrainCranial nerves Spinal cordSpinal nerves

Q7.What is difference between Endocrine and Exocrine gland? Q8. What is internal environment of cell? extra-cellular fluid Q9. What is extra-cellular fluid? Interstitial fluid 5 EndocrineExocrine DuctlessHave ducts Secrets directly into the bloodSecretion to outside of the body

Q10. For Homeostasis, what factors should be maintained constant? -supply of nutrient -concentration of O2 and CO2 -waste product concentration -pH as acidity affects enzyme activity -concentration of water and electrolytes - Temperature, narrow limit 35-38c - plasma volume and Blood pressure Q11. What is function of Immune System? Kill pathogens( bacteria, viruses, cancer cells..etc) -provide immunity – recognition of cells Q12. What are two control/regularity systems of body? Nervous System + Endocrine System 6

Q13. What is negative feedback mechanism? Give one example. In Negative Feedback, response occurs to restore to the normal (by moving the factors in the opposite direction of its initial change). Example: 1. If CO2 increases in the body, there will be respiratory stimulation which will try to wash out CO2 and bring it back to the normal. It is Negative Feedback mechanism. 2. If blood sugar decreases, body will try to increase blood sugar. It is Negative Feedback mechanism. Q14. What is positive feedback mechanism? Give one example. Positive Feedback mechanism amplifies (increases) the initial change, so that initial change is increased. Example: Oxytocin causes powerful contraction of uterus and causes release of more Oxytocin,which causes even stronger uterine contractions. Positive Feedback does not stop until baby is born. 7

Lecture 4: Inter Cellular Communication & Signal Transduction 8

Q1. How cells communicate with each other A.Direct Communication (give 2 methods) Gap Junctions Surface Markers A.Indirect Communication (give 4 methods) 1) Paracrines 2) Neurotransmitters 3) Hormones 4) Neurohormones Q2. Define paracrine way of communication and draw diagram to show. Local chemical messengers Exert effect only on neighboring cells in immediate environment of secretion site through Interstitial fluid Q3. What is the way of communication between nerve and muscle? Neurotransmitter 9

Q4. What is the hormone? How hormone act on the target cell? long range chemicals messengers Secreted into blood by endocrine glands in response to appropriate signal they effect on target cells( bind to the receptor) Q5. What is Neuro Hormone? Hormones released into blood by Neurosecretory neuron Ex: ADH, Vasopressin Q6. Define Signal Transduction. Carrying out the massage Q7. How signal transduction occurs? 1. By opening or closing chemically gated receptor channels e.g. Na+, K+ 2. By activating receptor – enzyme e.g. protein kinases 3. By activating second messenger via G-Protein 10

Q8. Name two important second messengers activated by G- protien. 1. Cyclic AMP [cAMP] 2. Ca 2+ Q9. In what way drugs are acting on the cell membrane? Second messenger { I am not pretty sure about this answer Q10. Name the protein which is activated by second messenger Ca 2+ inside the cell. calmodulin 11

Cell Membrane & Membrane Transport Lecture 2 & 3 12

Q1. What is composition of Cell membrane? lipid bilayer + protein Q2. What is Diffusion? Is it Passive or Active process? Moving from higher concentration to lower concentration”downhill” through permeable membrane, Passive Q3. What factors affect the Diffusion? Concentration gradient( C) Permeability of membrane (P) Surface area of the membrane (A) Molecular wt of the substance(MW) Thickness of membrane( X) 13

Q4. What is facilitated Diffusion? Is it Active or Passive Process? Diffusion of specific particles through transport proteins ( protein carrier) found in the membrane, passive Q5. What is difference between Diffusion and Facilitated Diffusion? Q6. Name the Passive processes of transport across the cell membrane. 1.Diffusion 2.Facilitative Diffusion 3.Osmosis 14 DiffusionFacilitated No need for protein carrier Protein carrier BOTH ARE PASSIVE

Q7. Give the characteristics of Primary Active Transport. Requires direct use of ATP ( energy is needed) Need protein carrier Uphill= low consternation to high Q8. What is Secondary Active Transport? Driven by an ion concentration gradient established by a primary active transport system Transport of two or more solutes are Coupled. Q9. What is chemical gradient? concentration of ion Q10. What is electrical gradient? charge of ion Q11. What is Electro chemical gradient? Both Electrical charge and concentration gradient Q12. What is Osmosis? a selectively permeable membrane diffusion of water through a selectively permeable membrane 15

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Q16. What is Osmolarity of Plasma? ml osm Q17. What is Vesicular Transport [Endocytosis, Exocytosis] ? Q18. Does vesicular transport require carrier? no Q19. Is Vesicular transport active or passive process? Active= energy is needed 17 taking bulky material into a cell “cell eating” Cell changes shape – requires energy Hormones or wastes released from cell