Physiology NMU part 11111

NA,K,Ca ions conc. in ICF and ECF respectively

NA,K,Ca ions conc. in ICF and ECF respectively

Cl,HCO3,Proteins conc. in ICF and ECF respectively

total body water in an adult man ?

woman ?

infant ?

old age ?

in adult men 60%

in adult women 50%

in infants more than 70%

in old age 45%

if the ECF amount is 14 litre its composed of ?

9.5 L interstitial fluid

3.5 liter plasma

1 liter transcellular fluid

2 examples of nega. feedbacks

and 2 examples of positive feedback

which one is more common ?

ممكن تقول الاسم بس لو فاهمه وهكتبه الامثله متفصله للتسهله

negative feedback :

1-(↑ CO2 (stimulus) → hyperventilation (response) → washout of excess

CO2 → ↓ CO2 to normal

2-↑ arterial blood pressure (ABP) (stimulus) → reflex vasodilatation and

↓ heart rate (response) → ↓ arterial blood pressure back to normal

positive feedback :

1-Death cycles→ fatal cycles leads to death

• In heart failure → decreased cardiac output (stimulus) → decreased

arterial blood pressure → decreased coronary blood flow (response) →

more heart failure

2-Some positive feedback cycles are useful

e.g. during labour:

• During delivery of the baby, the dilatation

of the cervix (stimulus) → increases the

uterine contractions→ descent of baby →

more cervical dilatation → more uterine

contractions (response) → more descent of

baby, till complete labor

.

.

.

negative feedback is the most common type of feedback

cell membrane thickness

7-9 nm

enumerate the components of cell membrane with % of each

42% lipids

55% proteins

3% carbohydrates

name the 3 types of cell membrane lipids

and the 2 types of cell membrane proteins

cell membrane lipids

1- phospholipids

2- cholesterol

3- glycolipids

cell membrane proteins

1-integral proteins

2-peripheral proteins

compare between integral and peripheral proteins

compare between the 3 types of ion channels

name the 3 types of diffusion and mention the 2 mechanisms of simple diffusion

1- simple diffusion

2-facilitated diffusion

3-osmosis (water only)

Mechanisms:

a) Through lipid interstices e.g. transport of lipid

soluble substances e.g. O2 and CO2 through cell

membrane

b) Through ion channels e.g. transport of ions such

as Na and K+

compare between simple diffusion,facilitated diffusion and active transport

what is ficks law

متقولش الاسم بس قول كل واحد يعني اي

describe the action of NA-K pump and how much energy does it utilize

• It transports 3 Na+ ions from ICF to ECF and 2 K+ ions from ECF to ICF.

• This maintains low intracellular Na and high intracellular K.

• It utilizes about 40% - 50% of energy

what is primary active transport and its types ? 3

obtain its energy directly from the hydrolysis of ATP e.g.

Na-K Pump, Ca ATPase,

H-K ATPase

what is secondary active transport and its types ? 2

use the energy stored in the Na concentration gradient

e.g.

Na-glucose co-transport and Na-Ca exchange

compare between the 3 types of endocytosis

name and examples

examples of exycytosis

Release of hormones, digestive enzymes,

and synaptic transmitters

what are the 3 types of intercellular connection

1-tight junction (zonula occludens) APICAL BORDER OF THE CELL

2-desmosomes (zonula adherens)

HEMIDESMOSOMES AND FOCAL ADHESION ATTACH CELLS TO THEIR BASAL LAMINAS

3-gap junction

compare between the tight and gap junction (definition, site and structure)

compare between the function of tight and gap junctions

mention the 4 types of intercellular communication and compare between them

what are the 3 stages of cell signaling

and what are the 2 types of cell receptors

1-reception

2-transduction

3-response

.

1-intracellular receptors

2-cell surface receptors

discuss the intracellular receptors

يهمني تعرف انواع ال intracellular

والفرق بين النوعين

discuss the cell surface receptors

and what are the 3 main types of membrane receptors

p71

1-ligand gated ion channel receptors

2-G protein coupled receptors

3- tyrosine kinase receptors (enzyme linked receptors)

discuss ligand gated ion channels

فسيولوجي بقا

discuss G-protein coupled receptors

describe tyrosine kinase receptor (enzyme linked receptor)

example of ligand gated ion channel

cholinergic nicotinic receptors

example of G protein coupled receptors

alpha and beta adrenoceptors

example of enzyme linked receptor

insulin receptor

example of intracellular receptors

steroid receptors and thyroid receptor

in g protein coupled receptor alpha subunit interact with ? whose activation forms ?

adenyl cyclase

or phospholipase C in the cell membrane

o Activation of an enzyme causes excessive

production of 2nd messengers inside the

cells such as cAMP (by adenyl cyclase), IP3

and DAG (by phospholipase C)

in G protein coupled receptor

adenyl cyclase is activates ?

phospholipase c activates

which do what ????

cAMP (by adenyl cyclase),

IP3 and DAG (by phospholipase C)

THEY PRODUCE INTRACELLULAR RESPONSE

types of neuroglial cells

in CNS ?

in PNS ?

in CNS : astrocyte,oligodendrocyte,microglia,ependymal cells

in PNS : satellite,schwann cells

pnsالاتنين اللي في ال

sبيبداو ب

astrocyte cells function

a type of neuroglial cells in CNS

maintain extracellular environment , remove excess neurotransmitter , direct neural growth , induce blood brain barrier in CNS

satellite cells function

a type of neuroglial cells in PNS

maintain extracellular environment , remove excess neurotransmitter , direct neural growth

oligodendrocyte cells function ?

a type of neuroglial cell in CNS

they create myelin

schwann cells function ?

a type of neuroglial cells in PNS

they create myelin

microglia cell function ?

a type of neuroglial cells in CNS whose function is

immune surveillance and phagocytosis

ependymal cells function ?

a type of neuroglial cells in CNS

create and circulate cerebrospinal fluid (CSF)

structure of neuron ?

1- cell body

2- axon

3-dendrites

4- presynaptic terminals

مش ستايل كارت اوي بس مهمه فشخ اوعي تفوتها

وصف ال myelin sheaths & schwan sheaths

the axon terminals make junction with 3 ?

and explain each

i) Dendrites or cell body of another neuron to form neuroneural junction or synapse

ii) Muscle fibers to form neuromuscular junction

iii) Secretory gland to form neuroepithelial junction

types of neurons physiologically and histologically (mention examples of each respectively)

physiological types :

sensory,interneurons,motor neurons

histological types :

bipolar,unipolar,multipolar

resting membrane potential in

nerves

skeletal muscles

cardiac muscles

smooth muscles

o Nerves: -70 mV.

o Skeletal muscles: -90 mV.

o Cardiac muscle: -90 mV.

o Smooth muscles: -60 mV.

goldman hodgkin katz equation is for ?

and it is ?

what is the distribution of ions inside and outside the cell for

Na

K

Cl

respectively

• ECF: ICF ratio for Na+ ions is 10: 1

• ECF: ICF ratio for K+ ions is 1: 35

• ECF: ICF ratio for Clions is 25: 1

comparison between permeability of cell membrane to K and Na ions

(the cell membrane is 100 times more

permeable to K ions than for Na ions.)

what inhibits the Na-K pump and what does this inhibition lead to ?

Any condition decreases the metabolic activity of

the cell

e.g. by cooling will inhibits

Na-K pump

so, Na+ ions will accumulate inside the cell and neutralize the -ve charges of protein ions -K ions that held on the outer surface escape away, and RMP becomes progressively lost

What forces contribute to the resting membrane potential, and what is the percentage of each force?

• 90-95 % of RMP is a passive

process due to diffusion of ions

thorough leak ion channels

• 5-10% of RMP is active process

due to the electrogenic Na-K

pump i.e. about 4-5 mV

firing level which lead to opening of al Na channels ?

-55 mV

hyperpolarization ?

K ions continue to diffuse to outside due to delayed

closure of its channels leading to hyperpolarization

monophasic recording of action potential consists of 3 parts

1-latent period

2-spike potential

3-after potential

latent period is ? caused by ?? duration affected by ??? importance ????

Def

• Is the time between the stimulation of the nerve

(marked by stimulus artifact) and the start of the

action potential.

Cause:

• Represents the time taken by the impulse to

travel from the site of stimulation to the site of

recording electrodes

Duration Is affected by:

1. The distance between the stimulating and recording electrodes.

2. The velocity of conduction of the nerve fibers Importance:

• Used to calculate the velocity of conduction of

a nerve fiber

steps of monophasic recording of action potential

دا مش سؤال خد بصه عالبتاع بس

compate between the 2 after potenntial waves ?

action potential is initiated in ? propagates where ?

Action potential is initiated at the initial segment

(axon hillock) and propagates

along the axon down to the terminal ending

compare between the 2 types of propagation of action potential

speed of conduction of action potential depends on what and what happens in multiple sclerosis disease

speed of conduction of action

potential depends upon the degree of

myelination

.

In multiple sclerosis, loss of myelin sheaths

causes decrease in conduction velocity

orthodromic vs anntidromic conduction propagation direction ?

describe the absolute refractory period

and its mechanism

and its signnificance

• During this period the excitability of nerve

fibers is completely lost i.e. no other stimulus,

no matter how strong will excite the nerve.

• It corresponds to the upstroke of depolarization

and early part of rapid repolarization

Mechanism

i. During upstroke all voltage gated Na+ channels are opened

ii. During rapid repolarization, inactivation gates

of the Na+ channel (h gates) are closed and they

remain closed until repolarization occurs Significance of ARP:

1. It limits the No. of impulses that can be initiated and propagated by the nerve fibers

2. Allow the conduction of nerve impulse in one direction, because the repolarized area or node is still in refractory period, so the resting area respond to the local currents and depolarize and so on

بصراحه مش عايز اشيل كلمه منها معلش

describe the relative refractory period and its mechanism

The excitability of the nerve fibers during this period is partially recovered and the nerve respond to stimuli of higher intensity

• It begins at the end of the absolute refractory period and continues until the membrane potential returns to the resting level.

.

Mechanism:

• During this period, the K+ conductance (current)

is higher than at rest, so strong stimuli are

required to make more inward current (Na+ current) to bring the membrane to threshold

compare between local excitatory state (graded potential) and nerve impulse (action potential)

points :

amplitude , summation , threshold , refractory period , conduction , duration , nature.

compare between tybe A,B,C nerve fiber

myelination , site , diameter , nerve impulse , speed , sensitivity , subtype ?

name the 3 physical factors and their effect on excitability and conductivity of nerve fibers

i) Warming →↑es the excitability and conductivity by

increasing the kinetics of ions leading to rapid

depolarization and repolarization

ii) Cooling →↓es the excitability and conductivity

b) Mechanical:

• Deep pressure ↓es the excitability and conductivity of

type A nerve fibers

examples of anesthetic drugs and what is their effect on excitability of nerve fibers (what do they block)

caine اي حاجه اخرها

cocaine, novocaine and xylocaine

→ block Na channels and prevent depolarization, so decrease the excitability of nerve fibers

2 examples of neurotoxins and what are their effect on excitability and conductivity of nerve fibers ?

1. Tetrodotoxin block Na channels, so prevent depolarization

2. Tetraethylammonium (TEA) block K channels, so prevent repolarization

Ca ions effect on nerve excitability ?

Na ions effect on nerve excitability ?

K ions effect on nerve excitability ?

wtf is anelectrotonus ?

wtf is catelectrotonus ?

causes of nerve block ? 7

1- thermal (by severe cooling)

2- mechanical (by deep pressure)

3- local anaesthetic drugs

4- increased Ca ions

5- decreased Na ions

6- decreased K ions

7- by strong anaelectrotonus

explain multiple sclerosis ?

• It is an autoimmune disease that affects persons between the ages of 20 and 50

and affecting women about twice as often as men

• It is due to both genetic and environmental factors

• In MS, autoantibodies attack myelin, causing inflammation and injury to the

sheath and eventually the nerves that it surrounds

rest of multiple sclerosis

• Signs include muscle weakness, fatigue, diminished coordination, slurred speech, blurred or hazy vision, bladder dysfunction, and sensory disturbances • All signs and symptoms are due to reduction in conduction velocity due to ; 1. ↓ Myelin → ↓ membrane resistance → causes current leaks out during electrotonic conduction, so current decays and velocity decreases 2. Leak of K ions through voltage gated K channels → K efflux → hyperpolarization of the cell membrane →↓ conduction velocity • Usually treated with steroids to suppress the immune system and decrease antibodies formation

units of measurement oof pressure are ?

mmHg and Cm H2O (1 mmHg = 1.36 cm H2O = 1330 dynes/cm2)

hydrostatic pressure law is ?

how much does pressure rise for each 1 cm down

vascular distensibility is ? law ?

veins distensibility in relation to arteries ?

pulmonary artery distensibility in relation with pulmonary vein ?

blood pressure in pulmonary circulation in relation to that in systemic circulation ?

veins are 6-10 times more distensible

pulmonary artery has distensibility 1/2 those of pulmonary veins

blood pressure in pulmonary circulation is 1/6 of those in systemic circulation

vascular compliance is ?

law ?

a highly compliant vessel vs a non compliant vessel?

compliance of a vein in relation to its corresponding artery ?

the compliance of a vein is about 24 times of its corresponding artery

how does the following affect compliance (respectively)

sympathetic nervous system

hormonees

vessel wall

blood flow law (ohm's law)

the poiseuille equation

p178

what are the 3 direct methods for blood flow measurement

1- electromagnetic flowmeter

2- ultrasonic flowmeter or dopler US

3- venous occlusion plethysmography

indirect method of measurement of blood flow

compare between laminar blood flow and turbulent blood flow

blood velocity law and cross sectional area of capillaries in relation to aorta

nerve cell is ?

number ?

structure ?

types of neurons are 3 ?

1. Afferent (sensory) neuron→ carries impulses from

receptors to CNS.

2. Efferent (motor) neuron→ carries impulses from CNS to effector organs.

3. Interneuron (associative)

→located entirely within CNS

pathway of the reflex action 5 ?

types of reflex action 2 ?

pathway :

1-sensory receptor

2-sensory neuron

3-interneuron

4-motor neuron

5-effector organ

.

types of reflex actions are classified according to effector organ into

1-autonomic reflexes (smooth muscles)

2-somatic reflexes (skeletal muscles)

PNS nerves are 2 types ? and their number ?

1. Cranial nerves → 12 pairs

2. Spinal Nerves → 31 pairs

(each pair arises from each

segment of spinal cord)

SPINAL NERVES ARE MIXED NERVES CONSISTS OF

1- AFFERENT (SENSORY) NERVES

2- EFFERENT (MOTOR) NERVES

REST OF DATA MENTIONED BEFORE

compare between somatic and autonomic N.S

control ?

connections ?

center ?

compare between the motor nerve fibers of somatic and autonomic N.S

compare between somatic and autonomic NS about

effect of denervation and chemical transmitters

ANS is subdivided into ?

A. Sympathetic (thoracolumbar) NS

B. Parasympathetic (craniosacral) NS

sympathetic N.S origin ?

Sympathetic N.S.(thoracolumbar) :

• LHCs of

1. All thoracic segments

2. Upper 3 lumbar segments of the spinal cord

parasympathetic N.S origin ?

Parasympathetic (craniosacral ) :

A) Cranial part:

1.Oculomotor N. in midbrain.

2.Facial N. in pons.

3.Glossopharyngeal N. in MO.

4.Vagus nerve in MO.

B) Sacral part:

• S2,S3,S4 and forms pelvic nerve

ganglia are ?

function ?

types 3 ?

Def.,

• Are collection of cell bodies of neurons outside the central nervous system (CNS)

Functions:

• Act as a relay station for autonomic preganglionic nerve fibers

• Act as distributing center:

sympathetic : preganglionic to postganglionic = 1: 32

parasympathetic: preganglionic to postganglionic = 1: 2

.

types :

1-lateral (paravertebral) ganglia

2-collateral (prevertebral) ganglia

3-terminal ganglia

describe the (lateral ganglia)

(Paravertebral) ganglia:

• Located on either side of the spinal cord

• About 22-24 ganglia on each side

• Form 2 rows of sympathetic chain of ganglia

• Act as a relay station for preganglionic sympathetic N. fibers only

describe collateral ganglia

(Prevertebral) ganglia:

• Present mainly in the abdomen, midway between spinal

cord and viscera

• Act as a relay station for sympathetic preganglionic N. fibers

describe terminal ganglia

• Present close to or at the wall the effector organs especially

rectum, urinary bladder and reproductive organs in the

pelvis

• Act as a relay station of:

a) All parasympathetic preganglionic fibers

b) Some sympathetic preganglionic fibers