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General physiology Flashcards

1
Q

What is homeostasis?

A

There are many things in our body which need to be constant for body functioning at its best..these include body temperature, pH, blood cells concentration, blood pressure etc .there are many more..these all things need to be maintained within a normal range. So maintenance of nearly constant internal environment is called homeostasis

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2
Q

Cell Count in human body

A

100 trillion

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3
Q

Rbc count in human

A

25 trillion

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4
Q

Why nearly constant internal environment needed?

A
  • The most crucial part of metabolic reactions in living bodies is enzymes i.e. biocatalyst. These make reactions occur at a very fast pace and metabolism too. But they have few conditions to perform at peak which includes pH, temperature, substrate & product concentration, few cofactors,etc. These enzymes perform optimum only under a range of these things. So if these won’t be in a normal range enzymes won’t work and metabolism will stop which will stop the energy formation and utilisation and therefore body functioning will get disable.
  • Along with enzymes there are organs which will function good when they will have good conditions..like heart if b.p. increases it will have trouble in pumping blood as high bp will generate high resistance which need more strength by heart to pump blood as it does in normal bp range
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5
Q

How homeostasis is maintained?

A

• Body have feedbacks mostly are negative.

  • Negative feedback: if any change will happen in body will try to compensate it by inhibiting the process changing it. Examples are product inhibiting enzyme, adrenal hormone inhibiting CRH & ACTH, blood pressure increase activating receptors which further lead to changes like vasodilation or any hormonal mechanism.
  • Positive feedback: there are only few positive feedbacks which ultimately have motive of normalising things. These includes clotting factors stimulating each other and increasing number to many times thus increasing the process of healing, nerve action potential travel one part of axon stimulating next part, during parturition contraction of uterus increasing many folds leading to baby ejection.
  • Feedforward feedback : these are delayed negative feedback helps in process of adaptive learning.

• These all feedbacks are done by two regulatory mechanism of our body includes-

  • Nervous system : it is fast, short life regulation
  • Endocrine system : it include hormones, it have long life but act slowly.
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6
Q

Cell membrane constituents?

A
  • Lipid bilayer..lipids- phospholipid(25%) & cholesterol(13%), other lipids(4%)
  • Protein- integral & peripheral -55%
  • Carbohydrate(3%)- glycocalyx, proteoglycan, glycoproteins, glycolipids.
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7
Q

Types of protein in cell membrane for transport?

A
  • Channel protein- they have channel in btwn them for transport
  • Carrier protein- they undergo conformational changes for transport
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8
Q

Types of aquaporins

A

13

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9
Q

What is pinocytosis?

A

Ingestion of small particles or molecules along with surrounding ecf

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10
Q

Phagocytosis

A

Ingestion of large molecules or even pathogens by making vesicle around it with cell membrane

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11
Q

Pinocytosis steps

A
  1. Receptors on cell membrane come in touch with molecules outside in coated pits
  2. Clathrin inside the membrane makes the membrane invaginate around the molecules
  3. Cell membrane dissolves at ends and fuse together making a vesicle having surrounding ECF too
  4. Now molecules inside the vesicle are digested with lysosomes they secrete their enzymes in the vesicle
  5. Digested food is taken by cell & organelles & left undigested residual bodies are egested out by exocytosis
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12
Q

Gating of channel proteins

A
  • Voltage gating

* Ligand gating

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13
Q

K+ channels specificity

A

It have 4 subunits of protein which have pore loops indulging in and form selectivity filter. These have carbonyl oxygens on it around central pore. As K is bigger than Na so Na is not able to make through it well..K interacts with carbonyl oxygens and get dehydrated and go into channel protein.

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14
Q

Na channel dehydration and activity

A

Channel is closed and have a negative charge in it which dehydrates Na and also make it active when needed

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15
Q

Active transport types

A
  1. Primary active transport- uses ATP directly and helps the energy in transport
  2. Secondary active transport- ATP energy is indirectly stored in some other form of energy could be concentration potential energy which will help in transport of lipophobic substances
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16
Q

Diffusion rate depends on?

A
  • concentration gradient
  • temperature
  • permeability of membrane to that substance
  • solubility in lipids
  • size of substance and mass too
  • pressure difference
  • electrical potential- nernst equation _+61/z ×log Cin/Cout
17
Q

Difference in simple diffusion and facilated diffusion

A
  • lipophobic substance in facilated diffusion
  • saturation point in facilated diffusion
  • membrane transport protein needed in facilated diffusion
18
Q

Secondary active transport example

A

Na-glucose cotransporter
Na- amino acid cotransporter
Na-H antitransport

19
Q

Na+-K+ ATPase

A

3 Na+ out
2 K+ in
ATPase inside
Act as-
•osmotic balancer- by decreasing amount of ions inside and putting Na out whose permeability is less so takes more time to diffuse in
•electrogenic- as it decreases one positive ion inside in comparison to outside so maintains a resting potential gradient

20
Q

Fluid compartmentalisation

A

•Fluid in human body - 50-75%; 50% in women, 60% in men(40l), 70-75% in children
•40% ICF(28l)
•20% ECF(14l) which is divided into:
-interstitial fluid(11l)
-plasma(3l)
There is also transcellular fluid which includes synovial fluid, CSF, etc. It comprises about 12l.
Blood is different fluid comprises of 5l

21
Q

Concentration of ions in ecf & icf

A 
Ecf:
 Na- 140 mEq/l
 K- 4 mEq/l
 Cl- 106 mEq/l
Icf:
 Na- 10 mEq/l
 K- 140 mEq/l
 Cl- 4 mEq/l
22
Q

Mileu interior

A

Internal environment which is ecf in which cells live.

23
Q

Homeostasis word

A

Walter cannon 1929

24
Q

Gain of a control system

A

Correction÷ error

25
Q

Fluidity of membrane

A

Cholesterol by determining water permeability

26
Q

Difference between lysosomes and peroxisome

A

• synthesis
Lysosomes by Golgi and peroxisome by ER
•enzymes
Lysosomes have hydrolases and peroxisome have peroxidase

27
Q

Nucleolus

A

RNA+protein

28
Q

Opsonization

A

Intermediation of antibodies in phagocytosis of bacteria

29
Q

Lysosome as bactericidal agent

A
  • add lysoferrin bind iron before they promote bacteria growth
  • lysozyme dissolve bacterial membrane
  • acidic pH
30
Q

Intercellular connection

A
  1. Tight junctions
  2. Gap junctions
  3. Adherens junctions
  4. Desmosomes
  5. Hemidesmosomes
31
Q

GLUT types

A

12

Glut 4 - insulin sensitive

32
Q

Osmotic pressure

A

Pressure on the solution side to stop the inflow of water through selectively permeable membrane from other true water side

33
Q

Why op depends only on osmolarity i.e. onle concentration not mass

A

Bcoz op is pressure applied by the solutes which will depends on their kinetic energy which will be equal as heavy body will have low velocity and lighter one with high velocity.So at last it will depends only on concentration of ions and solute

34
Q

Cellular sheet

A

Two opposite sides ,both have to be crossed so act together as sheet of cell

35
Q

Water loss

A
  • Insensible water loss(600-700ml)- unconsciously lost water from body which includes: 1. Respiratory loss- air before expiration is moistured to increase its vapour pressure till body’s. In cold weather more loss due to decreased atmospheric vapour pressure. 2. Skin loss- this is decreased by cornified skin cells which are lost on burn so increasing the loss.
  • Sweat loss- variable acc. to climate, exercise, metabolism , etc.
  • Loss in excretion(1400ml) and feces(100ml).
36
Q

Water intake

A
  • From metabolism(200ml)

* Fluid ingested(2100ml)

Mbbs (3 decks)

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