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Veterinary PathophysiologyStudent’s Lectures, 5th Semester

Department Clinical Pathology and Oncology,University of Veterinary Medicine

Introduction to Veterinary Pathophysiology

„There is only one rule: try to feel, think, and take action to become for the benefit of everythig.

There is only one knowledge, the others are just elongations:

The earth is below, the sky is above and the ladder in between is within you.”

Sándor Weöres (1913-1989)

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Introduction

Pathophysiology – General Clinical Pathology

Disease

Defectus, vitium

Disease as a sequence of events

Classification

Epidemology

Homeostasis

Osmoreceptor-ADH feedback

Indirect effect via aldosteron and Na+

Blood pressure regulations

PATHOPHYSIOLOGY and OTHER SUBJECTS

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Disease (Morbus)

Definition of disease

"Any deviation from or interruption of the normal structure or function of any part, organ, or system (or combination thereof) of the body that is manifested by a charasterictic set of symptoms and signs and whose etiology, pathology, and prognosis may be known or unknown"

/Dorland's Medical Dictionary/

One cause - one effect ?

Disease

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Components working togetherIt is not A + BIt is A + B + AB

An interaction can override any main effects

Agent Environment

Host

Schistosoma mansoni

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Defectus, vitium

CHARACTERISTICS OF DISEASES

• Health: characterized by physiological regulations

• Disease: characterized by physiological and pathological regulations

Disease Anomaly (deviation from normal) / \

dynamic process defect vitium

stable processes

Organism Enviroment - a delicate balance

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Anomaly (deviation from normal)/ \

defect vitium

stable processes dinamic

Anomaly

/ \defect vitium

congenital congenital, or acquired

http://www.hsvma.org/assets/pdfs/guide-to-congenital-and-heritable-disorders.pdf

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Examples of single defect: A) Dog with cleft palate; B) Eyelid coloboma (arrow) in a cat; C) Example of a multiple congenital anomaly in a dog (meningocele and peromelia).

Veterinary Dysmorphology Enio Moura, and Cláudia T. Pimpão

The Relationship between Brachycephalic Head Features in Modern Persian Cats and Dysmorphologies of the Skull and Internal Hydrocephalus

Journal of Veterinary Internal Medicine20 AUG 2017 DOI: 10.1111/jvim.14805http://onlinelibrary.wiley.com/doi/10.1111/jvim.14805/full#jvim14805-fig-0001

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Journal of Veterinary Internal Medicine20 AUG 2017 DOI: 10.1111/jvim.14805http://onlinelibrary.wiley.com/doi/10.1111/jvim.14805/full#jvim14805-fig-0001

Anomaly (deviation from normal)/ \

defect vitium

congenital congenital or acquired

Vitium Cordis

Medical definition of vitium cordis: An organic lesion of the heart.

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DISEASE AS A SEQUENCE OF EVENTS

Incubation

Crisis

Death

Recovery

Course

Cause Onset

Necropsy/Autopsy

Pathophysiology Clinical studiesPhysiology Physiology

Pathoanatomy

CLASSIFICATION OF DISEASES

1. with clinical symptoms/signs or without them (subclinical d.)

2. according to the length of the course:- peracute- acute (hum. < 3 months, complete recovery)- subacute- chronic (hum > 3 months, incomplete recovery)

3. genetic = abnormality of base sequence in the DNA of the fertilized ovum

4. congenital = existing at birth (not necessarily genetic)

5. acquired = due to the effects of some enviromental factor(s)

6. monofactorial/polyfactorial

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Manifestation classifications (cancer, stroke) are often more useful for treatment and management.

Etiologic (rat poisoning) classifications are more useful for prevention.

Epidemiology is often interested in biological phenomena with normal distributions.

Examples: •BLOOD PRESSURE• Epid.: hypertension

•BIRTH WEIGHT • Epid.: cachexia

•ADULT WEIGHT • Epid.: obesity

• INTELLIGENCE QUOTIENT (IQ)

• Epid.: mental retardation

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HOMEOSTASIS

Definition: the maintenance of stability in the internal environment ("millieu interieur", Claude Bernard) of the organism which is a precondition of life

Elements:

isovolemiaisoosmosis (isotonia)isoioniaisohydria(isothermia)

Regulation of the above elements are connected with each other, therefore deviation in any of them can affect the others.

Example: hyperthermia sweating hypovolemia, hyperosmosis(hypertonia)

The only reason to study them separately is didactic.

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Aims of restoring homeostasis

• RESTORING VOLUME RELATIONS HAS

PRIORITY over restoring other elements of

homeostasis to avoid fatal consequences of

HYPOVOLAEMIC SHOCK

• Therefore the effort of the body (and physitian!)

to restore normovolaemia may be associated

with disadvantageous side effects i.e.

simultaneous changes in isoosmosis, isoionia,

isohydria, isothermia

ALTERATIONS IN ISOVOLEMIA AND ISOOSMOSIS/ISOTONIA

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WATER BALANCE AND OSMOREGULATIONOsmoreceptor-ADH feedback

ADH secretion

osmoreceptors

increasedosmolarityof plasma

water loss

thirst center(hypothalamus)

water reabsorption in tubuli

decreased osmolarity of plasma

water intakeincreases

sensation of thirst

ADH secr. decreases

water loss increases

sensation of thirstdecreases

waterintakedecreases

Exogeneuscompensation

Endogeneuscompensation

1. WATER BALANCE AND OSMOREGULATION

(ozmoreceptor-ADH feedback) (direct effect via ADH)

AV3V, III. chamberanteroventral part of thethird ventricle

neurohypophysis

Henle loop ascendent ascendent part (distal tubule final part

area preoptica in front of

nucleus supraopticus

nucleus supraopticus

Verney mechanism

water loss,elektronic irritation, hypertonic NaCl injection into art. carotisba.,angiotensin II.

Plasma osmolarity: around 300 mOsmol/l (ions, small molecular weight organic molecules, proteins)

Osmolarity: 1 osmol/l osmolarity in a solution, when in 1 litre solution there is 6x1023 particles (molecules). EC=300 mosmol/l. (+,- 3%)

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1. WATER BALANCE AND OSMOREGULATION

(ozmoreceptor-ADH feedback) (direct effect via ADH)

ADH secretion

osmoreceptors

increasedosmolarityof plasma

water loss

thirst center(hypothalamus)

water reabsorption in tubuli

decreased osmolarity of plasma

water intakeincreases

sensation of thirst

ADH secr. decreases

water loss increases

sensation of thirstdecreases

waterintakedecreases

Exogeneuscompensation

Endogeneuscompensation

AV3V, III. chamberanteroventral part of thethird ventricle

neurohypophysis

Henle loop ascendent ascendent part (distal tubule final part

area preoptica in front of

nucleus supraopticus

nucleus supraopticus

Verney mechanism

water loss,elektronic irritation, hypertonic NaCl injection into art. carotisba.,angiotensin II.

Plasma osmolarity: around 300 mOsmol/l (ions, small molecular weight organic molecules, proteins)

Osmolarity: 1 osmol/l osmolarity in a solution, when in 1 litre solution there is 6x1023 particles (molecules). EC=300 mosmol/l. (+,- 3%)

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Osmometer

Osmolarity of body fluids (except urine): ~ 300 mOsmol/L, provided by ions, small organic molecules, proteins

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Osmomlarity, osmolar gap (OG)OG = measured serum osmolality − calculated osmolality

Calculated osmolality = 2 x [Na mmol/L] + [glucose mmol/L] + [urea mmol/L]

In non-SI laboratory units:

In this equation, the concentrations of urea and glucose in milligrams per deciliter are converted to millimoles per liter by the conversion factors 2.8 and 18.

A normal osmol gap is < 10 mOsm/kg .

Alcoholsethanol intoxicationmethanol ingestionethylene glycol ingestionacetone ingestionisopropyl alcohol ingestion

Sugarsmannitolsorbitol

LipidsHypertriglyceridemia

ProteinsHypergammaglobinemia (M. Waldenstroem)

SubstanceMolecular Mass

(da)

Contribution to

Osmolality

(mOsm/kg)

Albumin 69,000 0.144

Diatrizoate ion 613 16.313

Glucose 180 55.555

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2. WATER BALANCE AND VOLUME REGULATION(indirect effect via aldosteron and Na+ )

J.G.: juxtaglomerular apparatus. Juxta = latin preposition meaning near, nearby, close.

JGA: myoepithels of aff. arteriola, which are touching the dist. tubule retroflected part toward Bowmann-capsule, duty is the sensation of fluid content of the dist. tubule. Produces renin, whch cleaves decapeptide angiotensin I from angiotensinogen.

ACE

http://medcell.med.yale.edu/histology/urinary_system_lab/juxtaglomerular_apparatus.php

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Juxtaglomerul app arátus– tubuloglomarularis feedback –autoreg renal vérátáramlás, és GFR

1. afferens arteriola2. efferent arteriola3. macula densa4. extarglomerularis mesangium

Sympathetic nerve fibers reachthe afferent arteriole and innervate juxtaglomerular cells. An increase in sympatheticactivity stimulates reninsecretion.

2. WATER BALANCE AND VOLUME REGULATION(indirect effect via aldosteron and Na+ )

J.G.: juxtaglomerular apparatus. Juxta = latin preposition meaning near, nearby, close.

JGA: myoepithels of aff. arteriola, which are touching the dist. tubule retroflected part toward Bowmann-capsule, duty is the sensation of fluid content of the dist. tubule. Produces renin, whch cleaves decapeptide angiotensin I from angiotensinogen.

ACE

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2. WATER BALANCE AND VOLUME REGULATION(indirect effect via aldosteron and Na+ )

J.G.: juxtaglomerular apparatus. Juxta = latin preposition meaning near, nearby, close.

JGA: myoepithels of aff. arteriola, which are touching the dist. tubule retroflected part toward Bowmann-capsule, duty is the sensation of fluid content of the dist. tubule. Produces renin, whch cleaves decapeptide angiotensin I from angiotensinogen.

ACE

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67%

25%

5%

3%

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Low pressureStrech receptors

atrium

High pressureStrech receptors

Kidney JGA

+ CNC integrating function

+ direct consequences of hemodynamic and coll. osm.

changes

hypothalamus

Med. obl.

ANPMed. obl.

hypothalamus

renin-angiotensine system

..........................................................................................................................................

They have role in correction

Vasopressin

kidney(sympathetic ns.)

vessels

thirst

Chemoreceptor

Blood pressure regulations

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Glomerulotubular balanceTubuloglomerular feedback

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Tubuloglomerular feedback

TWO TYPES OF WATER BALANCE REGULATION

(SUMMARY)

Starting point:

• HYPEROSMOSIS HYPOVOLEMIA

osmoreceptors baroreceptors(volume receptors)

neurohypophysis J.G. renin-release

ADH-release angiotensin I,II,III

adrenal cortex: aldosteron release

H2O (direct) Na + H2O (indirect)

Baroreceptors: aortic curve, sinus caroticus (glomus aorticum, glomus caroticum),

Hypervolaemiabaroreceptors (arteriola dilation)increased interstitial space GFR and Na, water excretion increases, ANP, atrial natriuretic peptide(atrium)inhibition of Na-reabs.

atrial stretch receptors

arteriola narrowing

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TWO TYPES OF WATER BALANCE REGULATION

(SUMMARY)

Baroreceptors: aortic curve, sinus caroticus (glomus aorticum, glomus caroticum),

atrial stretch receptors

arteriola narrowing

TWO TYPES OF WATER BALANCE REGULATION

(SUMMARY)

Starting point:

• HYPEROSMOSIS HYPOVOLEMIA

osmoreceptors baroreceptors(volume receptors)

neurohypophysis J.G. renin-release

ADH-release angiotensin I,II,III

adrenal cortex: aldosteron release

H2O (direct) Na + H2O (indirect)

Baroreceptors: aortic curve, sinus caroticus (glomus aorticum, glomus caroticum),

Hypervolaemiabaroreceptors (artiriola dilation)increased interstitial space GFR and Na, water excretion increases, ANP, atrial natriuretic peptide(atrium)inhibition of Na-reabsa

atrial stretch receptors

arteriola narrowing

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