Cellular signaling Flashcards by Etienne Bingham

Compartments of the body and compostiton

Intra / Extra

Intracellular (Inside Cells):

40% K (Potasium)

Extracellular (Interstitial):

20% Transcellular fluid

NA (Sodium)high

NaCl NaHCO3

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Equilibrium State

Steady State

Equilibrium - NO transfer of a particular substance or energy from one compartment to the other

Steady State: does not change with time – the amount or concentration of a substance in a compartment is constant

Uses Energy to maintain the state

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GAP Junctions

AUTOCRINE

PARACRINE

NERVOUS

Endocrine

Gap junctions: adjacent plasma membranes - intercellular communication or transfer of low molecular- weight substances (made of connexin)

Autocrine: substance secreted by a cell acts back on surface receptors of the same cell

Paracrine: substance secreted by a cell acts on adjacent cells

Nervous: substance released by an axon terminal that influences a target neuron or cell

Endocrine: substance secreted by a cell that is distributed by the blood

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GAP Junctions

cells including cardiac and smooth muscle. (Contract in synsitium)

6 x connexin form a half channel called a connexon.

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Signal Transduction

Plasma Membrane Receptors

On plasma membrane or In Cell

(LIGAND) first messengers from transmitting cells can convert their info to a second messenger within the target cell

First messengers include peptides, protein hormones, growth factors, steroids, ions, metabolic products, gases, light

Second messengers include cAMP, cGMP, IP3, calcium, and DAG

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G protein-Coupled Receptors

Trimeric GTP-binding regulatory proteins

Respond to first messengers
Proteins, small peptides, amino acids, fatty acid
derivatives
Binding of ligand results in conformational change that allows the receptor to associate with a trimeric G protein in the inner leaflet of the plasma membrane
This association activates the G protein which dissociates from the receptor and transmits the signal to the effector enzyme or ion channel

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Basic Functions of the GI Tract

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Peritoneal Cavity

Omentum

Mesentary

Greater sack of Omentum - Gravitates to infection (Apendix to prevent the spread of infection

Mesentary- The access created by the Pariatal peritoneam for Art Veins and Nerves to Small intestine, Holds coils of intestine in place

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RetroPerineal

(Behind peritonium)

Organs

Access for SX from Behing Ribs

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Arteries of Abdomen

T8 inf Vena cava

T12 DIAphram

L4 Bifurcation of Aorta

Cecelia SMS Renzo Both the IM and AA

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Wall of GI tract

Inner - Circle

Outer -Long

Messenteric Plexis

Closed Viseral peritoneum

Muscularis Mucosa

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GI tract innervation

NA - Threshold / CA L-type Spike

Uniteric - Syncitium

Messenteric Plexes - Cells of CAJAL - Pace Maker

NA/K Atp ase

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Enteric Nervous system

Extension of CNS

Independent

VAGUS N Parasympathetic / Sensory

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Patterns of GI Motillity

Propulsion - Peristalsis

Tritiration -Antrum

Mixing

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GUT Reflexes

Gastroenteric

Gastroileal
Gastrocolic
Rectoanal - Puborectalis Msc

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Salavary Gland Secretions

Carbohydrate + Lipid breakdown start in the mouth

Inc PH with CL-shift antiporter for HCO3(into lumen)

Amylase

Lingual Lipase

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Gastric Secretion

PH<3 ihibits Gastrin

Parietal Cells- HCL/ Intrinsic Factor

Chief Cells. - Gastric Lipase Pepsinogen

HCL - Pepsinogen to PEPSIN

G-Cells - Gastrin

H2 Histamine - Incr HCL

Older Px - Decreased B12 (By intrinsic in Ileum) Causes Dementia

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ACID Production in Stomach

OMEPRAZOLE

Protein Pump Inhibitors

Overuse - Clostridium Difficle Infec

Pariental Cells

Special adaptation - ALCALINE TIDE Interstitial Fluid. Protect from high Acid

H / K ATPase ACID Produced

CL shift Alcaline tide

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Regulation of Stomach ACID

ACH - Para(Muscarinic) ATROPINE

Histamine (Pyloric glands) - H2 - ZANTAC / PEPSID

Parietal cells (Para) Protein in stroma

OMEPRAZOLE - H/K ATPase Proton Pump inhibitor

Block H Exretion

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3 Phases Of Acid Stimulation

Stim Parietal Cells Stomach

Intestine - protein Digestion Products

Cephalic(smell) - Para Vagus / Ach Gastrin

Gastic(distension) - Enteric Vago-Vagal - ACH Gastrin

Intestinal - Amino Acids in blood - Amino Acids

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Superior Mesenteric Vessels

Just anterior to Duodenum

Most of Pancreas and Duodenum

Retro Peritoneal

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Pancreatic Secretions

Neutralize PH Chyme - enzmes to work

Duct cells: CL shift

Cl into for HCO3

H to blood + ACID TIDE (Protect against alkaline)

NA to lumen H2O follow ISOTONICITY

Acinar cells - Pro-enzymes activated by trypsin

Na / Cl

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CFTR

Cystic fibrosis Transmembrane Conductance Reg

Cl out of cell to feul HCO3 exchanger

Uses ATP

Morbidity Lung infections

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Regulation Of

Pancreatic Secretions

Seritonin

CCK - Trypsin

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Functions of the Liver

Nutrient Stores - GLYCOGEN Metabolic Conversions **CYTOCHROME P450** Enzyme System Grapefruit juice decreases activity **Statins** **ITO Cell -** Main store of retinal Esters in liver

ITO CELLS

Portal Hypertension Venous obstruction , Occlusion

Asites Splemomegaly Hemroids Eosophical Varicies Caput Madusa

Biliary Tree / Gall Bladder

CCK - Contraction Blasser Open Sphincter Of Oddi

Bilirubin

Jaundice Ex Neonates UV light Break down Biliruben / Exessive breakdown of RBC / In utero more RBC Dt Low PO2

Regulation of Bile production

CCK Secritin

GALLSTONES

Clinical Px starts taking statins - (Excess cholesterol has to te removed)

Digestion Carbohydrates

Digestion PROTEINS

Double Bonded Lipid Ex OMEGAS

Lipid Digestion Lingual Lipase Acid Lipase Pancreactic Lipase

Micelle Structure moste Stable

Absorption of Vinamins And **Iron**

A D E K, Stored in cells

Endocrine Organs

Feedback Regulation Hormones Mostly NEG feedback

LH hormone the exception, POS feedback LH surge just before ovulation

Steroids

Polypetide and Protein Hormone production

Cleaved into subunits ACTH - MSH Corticosteroids - Melanin stim Hormone

Pituitary Gland

Anterior (Epithelial cells) - Tropic Posterior( Medial emminance of CN Tissue)

Hypothalamic Pituitary axis

Post Pituitary Hormone **Made by Hypothalamus** **SECRETED** by Post Pituatry Oxytocin ADH Vasopressin

Hypothalamic releasing hormones

Anterior Pituitary Hormones

Posterior Pituitary Hormone

ACTH Adenocorticotropic Hormone

ACTH + TRH(thyrotropin) Cercadian Rythm release Feedback only to Reticularis and Fasiclata **NOT Glomerulosa where only Aldosterone is made.**

Thyroid Gland:

T4 converted to T3 by Target cells Bind to Tg(Thyroglobulin) in CALOID Dietary Iodine important THS stimulates reuptake of Tg and release from same cell

Reverse T3

Thyroid Hormone functions

Goiter

Growth Hormone

GH stimulates **IGF 1 Insulin like Growth factor 1** Mitogenic factor **mediates** effects of growth Hormone Too Much - Acromegaly Too Little - Proportional Dwarfism

Adrenal Glands

Cortex (**GLUCOCORTICOIDS**): G - Aldosteroen F - Cortisol R - Androgens Mudulla - Cathicholamines

Adrenal Gland Cortex Hormone sythesis Addisons No feedback ACTH MSH Rate limmiting step

11 B hydroxylase **Deficient Women** **Backflow - Inc Androgens** Verilization Serious **Reduced Cortisol** Angiotension 2

**Aldosterone**

LOW BP

Glucocorticoids

Gives the brain what it needs Hormone sensitve lipase

Endocrine Pancreas

4 types of cells

Insulin Structure

Better insulin responce to ORAL than IV **Incretin Efecct** **SULFONY DRUGS effect**

CALCIUM Regulation

Calcitonin Parathyroid Hormone - Vit D (Calcifarol pathway in gut for absorption)

Vitamin D

Parathyroid Activation of Mature Vit D Facilitate the absorption of CA by Ca binding protein

Osteoporosis

Estrogen effect protect bone - increase Kidney and Intestinal uptake

Functions of the Kidney

Renin Eurithropoiten Acid Base Balance Degrade insulin and Parathroid hormone Na - H2O follows

Body fluid Composition

42 14 / 28 10.5/3.5L plasma 25%

Kidney function Renal Clearance

Glomerular Filtration Rate GFR 110-125mm/min

Most accurate - **INULIN** **Inulin** Clearance ratio Daily practice : **Endogenous creatin clearance**

Endogenous **Creatine Clearance** Rate

Constantly cleared, high value, slower clearance

Substances not found in Urine (uria)

Fasting blood glucose diabetic 127 mg% Threshold 180mg% - 200 before spilling into blood Phenylketoria - Test newborn for enzyme Cant bread down Phenylealamine to Thyrocine newborm test / food lable warnings

Renal bloodflow 20% of Cardiac output

Autoregulation of flow Myogenic mechahisn Tubulaoglomeric feedback

Determinants of GFR

Proximal Convulated tubule Large amount of Reabsorption

Acetazolamide Na / H Pump inactivated Na Stay in lumen H2O follow excreted in Urine

Loop of Henle

Furosemide (Assending Salts) Blocks transporter for reabsorption CL K Na HypoKalemia dt Duretic Decending **Only H20 leaves**

Distal Convulated Tubule

Thiazides Impermeable to H2O unless - Aldosterone ADH Na Ca pump interstitial side blocked Ca Na3 pump (CA gradient created) that get upregulated by Parathyroid hormone to add Ca to the blood. Large channel on lumen side thaCa enters

Cortical Collecting Duct Principal **- Secrete K** K out side with smalle elec Potential DiFF LOW BP - Adosterone Upregulates Na / H2O follows

Intercallated Cells - **Acid Base** **H K ATPase** More H pumped out the higher K HyperKalemia

Urinary Concentration and Dilution 2 counter current processes Countercurrent Multipliers Loops of henle / Set up gradient Countercurrent exchangers Vasa Recta / Prevents wash out

Urea in Concentration Mechanism

Dilute Urine ADH levels LOW

Concentrated Urine ADH levels HIGH

Diabetes **INSIPIDUS** ## Footnote **Polyuria**

Potasium Balance K

Risk in Diabetic Px recieving Insulin Hypokalemia Insulin - uptake of K

Emesis Vometting **xtracellular fluid Volume contraction**

H - loss HCO3 increase Alkaline shift Bigger issue - Ventilation + More HCO3 uptake

Juxtaglomerular Apparatus Macula Densa RENIN

RENIN Secretion 1. Beta Adernergic stimulation SYMP 2. Reduced Renal Perfusion pressure * *Detected By JG cells** 3. Decreased **NaCl reabsorption** by **Macula Densa** It Reduction in **GFR**