Circulation

70%

• only artery that carries deoxygenated blood
• only vein that carries oxygenated blood

• only in heart
• lie between each muscle cell
• provide stability
• allow rapid transmission of nerve impulse from one cell to another throughout the tissue

• control speed of transmission within cardiac muscle
• help coordinate muscle contraction

blood

9%

(7%-plasma 2%-corpuscles/cells)

• carries nutrients, oxygen, and water to tissues
• moves waste products to the organs responsible for their elimination/excretion 
• circulation of hormones&enzymes
• helps maintain body temp

7.4

90% water

• mineral salts (NaCl, calcium carbonate, potassium phosphate)
• plasma proteins (albumin, globulin, fibrinogen)
• dissolved gases (O2, CO2,Nitrogen)
• waste products (urea, creatinine)
• nutrients (glucose, amino acids)

varying levels of antibodies, hormones,& enzymes depending on the physiological status of the animal

millions

(5-7 million)

thousands

• dog: 11,000
• cat: 13,000
• horse: 9,000

HIGH

(viral infection: WBC low)

• erythrocytes (RBC)
• thrombocytes (platelets)
• leukocytes (WBC)

• granulocytes
• agranulocytes

• neutrophils
• basophils
• eosinophils

• lymphocytes
• monocytes

nucleus

(so can carry more oxygen)

transport oxygen from lungs to tissues of the body and carry carbon dioxide back to lungs

RBCs to transport oxygen and carbon dioxide 

in the lungs, oxygen in the inspired air combines with hemoglobin in the erythrocyte form to form this compound

the number of circulating erythrocytes and the amount of hemoglobin that each cell contains

• cat- 120 days
• dog- 110

then broken down primarily by spleen

• white pulp: destroys lymphocytes
• red pulp: produces lympophcytes

other sites also breakdown erythrocytes (liver, bone marrow)

liver

(remaining components converted into bile and excreted in feces)

thrombocytes

(non-nucleated)

assits with hemostasis (blood clotting)

leukocytes (WBC)

polymorphonuclear leukocytes

granulocytes (the 3 phils)

approx 70% of WBC count

neutrophils

(difficult to stain; hence neutral)

neutrophil

(phagocytosis)

eosinophils

esoinophils

basophils

(1% of total WBC count)

histamine and heparin

(released at the site of injury to promote inflammation)

vasodilation and reduced cardiac output (low blood pressure)

lymphocytes

lymph nodes and lymphatic tissue of spleen, liver, and other organs

• B-lymphocytes (antibodies)
• T-lymphocytes

humoral immunity

When activated, they produce and secrete the specific antibody for the invading antigen.

(short-lived immunity)

• humoral immunity/ B-cell immunity
• cellular immunity/ T-cell immunity

attack and destroy the invading cells directly

• (long-lived immunity)
• (primarily surface)

monocytes

monocytes

monocytes

basophils

• neutrophils
• monocytes

eosinophils

• tissues: macrophages
• liver: kupfer cells
• CNS: histocytes

hemopoiesis

lymphocytes that originate from lymph nodes, spleen, liver, etc.

erythropoiesis

(occurs in red bone marrow)

Anemia is a reduction in the total RBC count&/or a reduction in the hemoglobin concentration.

hemoglobin

amino acids, vit C, B6, B12, iron, and folic acid

(if any are deficient in diet of the animal, symptoms of anemia may develop)

erythropoietin

carry more Oxygen and CO2

(reptiles&avian do)

kidneys in response to a fall in the circulating levels of oxygen in the blood (hypoxia)

thrombopoiesis

occurs in bone marrow from large cells called megakaryocytes (precursors for thrombocytes)

peptide hormone secreted in the kidneys that controls the rate of thrombopoiesis by stimulating the production of megakaryocytes

production of leukocytes

occurs in bone marrow

they differentiate to produce all the different types of leukocytes except lymphocytes

• spleen
• thymus
• liver
• lymph nodes

• spleen
• thymus
• liver
• lymph nodes

thymosins

• assist in maintaining the required number of T-lymphocytes
• in the adult, production is related to exposure to antigens

thymus 

(in immature animals bc thats when developing immune system)

the stopping of a flow of blood

localized constriction of smooth muscle surrounding vessel that slows, or may even stop blood flow at the damaged site

endothelial cells lining the vessels become 'sticky' and platelets adhere to their surface (platelet adhesion) forming "platelet plug" usually occurs within 15 sec

• T-long memory (skin)
• B-short memory (distemper, rabies, corona virus)

alpha 1

When thromboplastin enters the plasma, the enzyme thrombokinase is formed, which converts prothrombin into thrombin. Thrombin then converts the plasma protein fibrinogen into insoluble strands of fibrin which is sticky and traps thrombocytes forming the blood clot.

always in the blood: prothrombin, fibrinogen, thrombocytes

• dog/cat: 3-5 min
• horse: 5-15

17 mm of mercury

• in purple tube: plasma
• in red tube: serum

calcium ions and vitamin K

• Ca: formation of thromboplastin
• K: 4 clotting factors, including prothrombin

deficiency of either will impair clotting

process where the clot gradually dissolves as the wound heals

the fibrin that formed the clot is broken down by the enzyme plasmin or fibrinase produced by plasminogen, the inactive form that circulates within the plasma and body fluids. 

Dog Erythrocyte Antigen

or Canine Erythrocyte Antigens

8 types

• DEA-1 (A1)
• DEA-2 (A2)
• DEA-3 (B)
• DEA-4 (C)
• DEA-5 (D)
• DEA-6 (F)
• DEA-7 (Tr)
• DEA-8 (He)

DEA 4&6 (98%)

DEA-3 (B)

DEA 1 and 2

• risk sensitization&subsequent severe transfusion reactions (must give their blood type next time)
• transfused RBCs will have shortened life

• through the vein (preferred)
• intraperitoneal (50% die, other 50% shortened lifespan)

A

• existence of strong preformed isoantibodies
• no universal donor in cats

(type B cats receiving A may have fatal reaction after only 1 mL of incompatible blood. type A receiving B milder reaction)

Type AB

• diarrhea (loosing sodium)
• vomitting (loosing chlorine) 

(give normal saline bc has sodium&chloride in it)

2.2 lbs in 1 kg

Vol= %increase X weight of animal X 1.7=mL

• Ex: 5 kg cat with PCV 14% (want 20%)
• 6% X 5 X 1.7= 51.0 mL of blood

10mL/Kg/Hr

hypovolemic cat- 60mL/Kg/Hr

where the exchange of nutrients, oxygen, and carbon dioxide occurs

• endocardium
• myocardium
• epicardium
• pericardial cavity
• serous pericardium
• parietal pericardium

AV valves close as ventricles contract

semi-lunar valves close as pulmonary artery and aorta contract

aorta

right

in the lungs, exchange of oxygen and CO2 occurs and oxygenated blood returns to the left atrium before being pumped around the body

force of contraction required to pump blood the shorter distance to the lungs (pulmonary circulation) is less than that needed to get all around the body (left ventricle leads to aorta-major artery supplying body)

systole- contracting

diastole- relaxing/filling

• atria filling (D)
• AV valves closed
• ventricles contracting (S)
• semilunar valves open
• pulmonary artery&aorta filling (D)

• pulmonary circulation (to lungs) Right
• systemic circulation (to body) Left

• top- systolic pressure
• bottom- diastolic pressure

120/80

deoxygenated blood pumped from R side of heart to lungs in the pulmonary arteries. blood is oxygenated at the lungs before being returned to the heart in the pulmonary vein. 

• pulmonary artery&vein
• umbilical artery

blood from L side of heart to the body tissues, via arteries and capillaries where it becomes deoxygenated before returning to the R side of the heart in veins.

• contact between cells via intercalated discs allows cells to contract simultaneously (heart appears to act like one large muscle)
• does not fatigue following repeated contractions
• rhythmic contraction without any nerve supply (automaticity)

R- tricuspid problem due to heartworms (blood backs up into liver)

L- mitral valve insufficiency (blood backs up into lungs "pulmonary edema")

• R- thinner wall
• restrictor bands

L- thicker wall

• overworked
• heartworms
• (anything that really works the heart)

preventing blood flowing in the wrong direction as the heart chambers contract

• mitral valve
• tricuspid vale

function: prevent blood flowing back into the atria as ventricles contract

attach to the chordae tendinae, contract and prevent the cusps of the valves being pushed back into the atria

• pulmonary valve
• aortic valve

function: prevent flow of blood into the ventricles following systole

• present at birth
• something happened between conception and birth to cause this

• pulmonic stenosis
• aortic stenosis (narrowing in valvular region)

develop with age

valve incompetence or valvular insufficiency-cusps of valves thicken and loose their elasticity causing valve to leak

mitral valve disease

usually first evident- general slowing down during exercise accompanied by breathlessness

start to cough, if left untreated will progress into heart failure, as the heart is unable to pump sufficient blood around the body

blood accumulates in the left atrium and may flow back into the lungs, causing pulmonary congestion, leads to pulmonary edema and dyspnea

• Blood goes through kidneys, kidneys measure
• BP drops below certain pressure, detected by Juxtaglomerular cell which in response releases Renin
• Renin takes Angiotensinogen and converts it to Angiotensin I
• Angiotensin I converted to Angiotensin II by Angiotensin Conversion Enzyme (ACE)
• Angiotensin II goes to the adrenal gland and causes the outer layer (zona glomerulosa) to release Aldosterone
• Aldosterone goes to kidney to cause absorption of Na
• So goes Sodium, so goes water: as Na is absorbed, water comes with it increasing the volume of blood thereby raising BP

Once BP increased, circulates (60 sec) to kidney, where it is measured, once normal, kidney will stop releasing Renin (negative feedback)

renin-angiotensin system

Enacard- ACE inhibitor. functions by blocking the conversion of Angiotensin I to Angiotensin II

liver

(always in blood)

generic name

• right side heart failure due to dirofilaria immitis 
• blood backs up in the vena cava (hyperemia) resulting in blood hyperstasis in the liver with liver failure and ascites in the latter stages

dilated cardiomyopathy (DCM)

• muscular wall of the heart becomes thin and lose ability to contract effectively
• etiology unknown
• more common in large breeds

• does not occur frequently in animals
• acute myocardial ischemia (blockage) is often secondary to other cardiac diseases, such as aortic stenosis, endocarditis, cardiomyopathy, or neoplasia

blood not getting to cardiac muscle which begins to die

• bacterial infection of endocardium
• usually involving a valve
• in dogs, most common affected valve-mitral

• contraction
• depolarization

• relaxation
• repolarization

systole

diastole

• contraction- depolarization
• relaxation- repolarization

• most common heart disease of cats
• disease of the myocardium
• left ventricular walls become thickened (hypertrophied) while the left ventricular chamber decreases in size
• clots form and break loose lodging in the iliac arteries with hind limb paresis

slow everything down bc parasympathetic nerve

• baroreceptors/pressoreceptors- measure pressure
• chemoreceptors- measure chemical composition of the blood

the cardiac center stimulates the heart to increase its output

this leads to an increase in BP and Oxygen content of the blood, with a corresponding decrease in the circulating levels of CO2

• measures the electrical activity of the heart
• assessment of hearts ability to conduct impulses

connects carotid sinus to respiratory and cardiovascular centers of the hindbrain

• initial stimulus- spontaneously in SA node(located in right atrium)
• wave of depolarization spreads across L&R atria as they contract, emptying their contents into ventricles
• upon reaching AV node(located in septum) wave of depolarization travels along bundle of his, spreading along purkinjie fibers
• ventricles contract, pumping blood into pulmonary artery&aorta to circulate to the pulmonary&systemic circuits

• sympathetic&parasympathetic can modify heartbeat (frequency&force of contraction)
• central area of control in medulla oblongata-receives/processes information from parasympathetic/sympathetic areas of hypothalamus

medulla receives feedback from baroreceptors&chemoreceptors-telling heart to either increase/decrease cardiac output

• constriction- heart beat up
• respirations up
• BP up

• dilation- heart beat down
• respirations down
• BP down

• CO2- increase respiration to balance it out
• O2- we will cause vasodilation&reduced cardiac output

QRS complex

common heart murmur in thoroughbred horses

PR interval- indicates how long it takes the impulse to travel through the AV node

impulse takes too long to get through and never reaches the ventricles

(PR interval will be increased)

right atrial enlargement (p-pulmonale)

left atrial enlargement (p-mitale)

left ventricular enlargement

right ventricular enlargement

massive block

depolarization

and subsequent contraction of the atria

QRS complex

(as the action potential is spread down the bundle of his to the purkinje fibers and the ventricles depolarize and contract)

repolarization

(recovery of ventricles prior to the commencement of another heartbeat)

depolarization of ventricles

rhythms too slow or too fast

• heart rate too slow-heart cannot pump adequate amount of blood to meet body's needs
• heart rate too fast-heart cannot fill with blood adequately and pumping function of the heart will be abnormal

bradyarrhythmia

tachyarrhythmia 

dog

(inhale-heart slows down, exhale-heart speeds up)

dysrhythmias

capillaries

• outer layer of arteries/veins
• formed from collagen and elastic fibers
• protects the vessel

• middle layer of arteries/veins
• contains smooth muscle&elastic fibers
• innervated by sympathetic, can contract or relax to control amount of blood flowing through vessel

• inner layer of arteries/veins
• single layer elastic fiber&flattened endothelial cells
• smooth surface for circulation

79-97

arteries

vasoconstriction

conversely, when the smooth muscle relaxes causes vasodilation

• left and right common carotid arteries &
• right subclavian artery

left and right subclavian arteries 

• sternocephalicus
• brachiocephalicus

veins

(have less elastic fibers, therefore, less stretchability than arteries)

• more accessible
• thinner walls
• consequences of damaging less severe (damage to artery may compromise blood supply to several tissues/organs)
• less chance of hematoma bc not under pressure like arteries

cranial and caudal vena cavae

azygous vein

carries absorbed products of digestion from intestine to the liver for detoxification

capillaries

cappillaries

• surround beginning of each capillary
• contract or relax to decrease/increase the flow of blood through the capillary as needed

autonomic nervous system

SLOW, in addition to decreasing the force of contraction.

this combined effect reduces cardiac output

increased heart rate, accompanied by an increased force of contraction.

this increases the cardiac output

causes stimulation to vagus (parasympathetic) so slows heart down 

(dog kicked in neck=40 BPM)

volume of blood pumped by the heart in a given time (60 sec)

cardiac output= stroke vol X heart rate


Ex: 10 mL X 180 BPM= 1800 mL/minute

Left

force that the blood exerts upon the blood vessels 

(greatest in the aorta-starts high in aorta and decreases to low as the blood finally enters the heart at the right auricle)

ventricular contraction

ventricular relaxation

decreases

vasoconstriction 

cause increase in metabolism of cells causing an increase in heart rate and force of contraction

bronchodilation=ease of respiration

• femoral
• cranial tibial
• brachial (bird)
• ulnar/carpal artery
• coccygeal (cow)
• carotid
• sub-lingual (pigs)

cardiovascular centers

• cardiac center: 2 regions
• one causes acceleration of heart rate via sympathetic, one causes deceleration via parasympathetic 

• vasomotor: 2 regions
• one causes vasoconstriction
• one causes vasodilation

• Cardiovascular Centers
•     1. cardiac center- 2 regions
• a)accelerate heart via sympathetic
• b) decelerate heart via parasympathetic
•     2. vasomotor center (control vessel width)
• a)vasoconstriction
• b)vasodilation

• *all based on pressure, O2, or CO2
• (pressure or chemical content of arterial blood)

• baroreceptors located in carotid sinus and aortic sinus detect the degree of stretch of the vessel wall.
• gives feedback about level of BP, allowing cardiac output and peripheral resistance to be adjusted accordingly

detect O2 or CO2 concentration (chemical content of the blood)

makes aortic arch and carotid sinus receptors more sensitive to CO2 concentrations (will make the animal breathe)

Ex: Doxapram (non-propietary)

carotid and aortic bodies

liver

kidney

lungs

• stimulates secretion of Aldosterone *water retention&we can control easily*
• stimulates secretion of antidiuretic hormone (increases water retention by kidneys)
• stimulates thirst
• vasoconstrictor (reducing blood flow to periphery to ensure blood flow to vital organs)

digitalis 

diuretics

vasodilation and reduced cardiac output.

• less than 10%- few signs
• 25%- tachycardia, mild-moderate hypotension
• 40% or greater- severe hypotension, may not recover if treatment not carried out w/in 2 hrs

severe hemorrhage, such as that caused by injury during a hit by car, ruptured splenic tumor, other internal bleeding or severe burns

hypovolemic (decreased vol of circulating blood in the body)

• pale mucous membranes with slow CRT
• extremities cold to the touch
• low BP
• increased heart rate with a rapid weak pulse
• may appear depressed

• compensatory shock
• progressive shock
• irreversible shock

all arterioles except coronary and cerebral vessels constrict to maintain arterial pressure and adequate circulation

• B1- heart faster&stronger
• B2- dilate coronary&cerebral vessels while dilating bronchioles
• A1-constrict peripheral vessels of skin&intestines

heart cannot pump enough blood for adequate coronary circulation resulting in decreased cardiac output. lack of blood to the brain damages respiratory center causing vasodilation and the shock cycle continues

• treatment at this point is of no value bc heart damage is irreparable
• capillaries become too permeable and death results within short time

SPO2 (measurement of oxygen attached to hemoglobin) and pulse

• normal SPO2= 95
• pulse 60-120

blood pressure (79-97 mm Hg)

• indwelling catheter in vein
• lactated ringers
• animal on heating pad
• elevate feet-blood flow w/ gravity back to heart
• give soludelta cortef or dexamethasone phosphate to conceal dilating vessels and allow to contsrict&stop anymore loss of plasma

administered to restore circulating blood vol.

• normal saline (0.9%)
• lactated ringers
• hartmann's solution
• dextrose, etc

longer shelf life

beneficial to administer before crystalloids to reduce amount of crystalloids needed

• plasma
• dextran

• remain in circulatory system longer
• short shelf life
• expensive

• IV fluid replacement may not be necessary
• oral fluids containing electrolytes

swollen muzzle from allergic reaction to vaccine

treat with soludelta cortef (swelling down so can breathe again)

(leptospirosis- not a virus; bacterin=bacteria will cause shock reaction)

• cause of shock
• histamine release
• vasodilation of capillaries
• increased capillary permeability
• blood plasma moves from blood into tissue
• decrease blood vol&pressure
• reduce blood flow
• histamine release
• vasodilation to reduce friction on blood flow
• etc...

• lymph nodes
• spleen
• thymus
• liver

• trash away from body
• protect body (antibodies)

drains tissue fluid (lymph)

• filter out infections (when does they swell up)
• defense against infection by harboring lymphocytes, plasma cells, and macrophages

• cortex (produces B-lymphocytes)
• paracortex (produces T-lymphocytes)
• medulla (accumulation of plasma cells)

• B-lymphocytes
• T-lymphocytes
• plasma cells

afferent lymph vessels entering the subscapular sinus and is filtered through the cortex, paracortex, and medulla, to emerge finally at the hilus, then efferent lymphatic vessels emerge and carry the lymph out

• located on left side
• lymphoid organ associated with circulatory system
• attached to the stomach by gastrosplenic ligament
• one of primary producers of lymphocytes

• parenchyma (tissue cells) of spleen:
• red pulp- engorged w RBC at the end of their life
• white pulp-B&T lymphocytes in abundance

120 days

• immunologic functions
• storage area for RBC
• worn-out RBC iron is stored here

not essential organ, its functions can be carried out by other organs but will be susceptible to parasite blood cell infections

thymus

where T&B lymphocytes go to get specific duties

• 6 total: 3 on each side
• lack afferent lymphatic vessels, relying on their proximity to the epithelial surface to make contact with antigens

O2 to tissues and CO2 away from tissues

inspiration and the diffusion of oxygen from the air sacs (alveoli of lungs) into the blood and CO2 from the blood into the air sacs

diffusion of gases between the blood and tissues of the body

reduction in number of erythrocytes and/or reduction of hemoglobin

• what oxygen attaches to
• made of heme- iron (yellow) and globin-protein

HgG =12.5 g/mL

• inspired air: 500/1
• expired air: 4/1

bronchi>bronchioles>alveoli

• bulbous enlargement that attaches to the wing of the nostril
• functions to cause turbulence of air entering the nasal chamber to ensure the air is warmed, moistened, and filtered prior to entering the rest of the respiratory tract

• highly vascular (to warm air as it comes in)
• lined with ciliated (to grab particles) mucous epithelial tissue to increase the surface area

• nasopharynx
• oropharynx
• laryngopharynx

• continuous from nasal chambers
• lined with ciliated
• eustachian tube from middle ear opens up here, to permit equilibration of the pressure on either side of tympanic membrane
• separated from rest of the pharynx by the soft palate

• below soft palate
• contains folds of lymphoid tissue known as tonsils
• lined with striated epithelial tissue to resist friction caused during swallowing

forms caudal part of pharynx and leads to larynx

• cranial end of trachea
• composed of muscle&fibrocartilage
• vocalization

• thyroid cartilage
• arytenoid cartilage
• cricoid cartilage
• epiglottis

hyperemia 

hyaline cartilage

(space in rings lie at the points where the esophagus expands during swallowing!)

ridge that marks the point of division of the trachea into bronchi

• caused by increased activity in sympathetic
• increases amount of air available
• preparing animal for "fight-or-flight"

• result of activity in parasympathetic
• reduces diameter of airways
• may occur in allergic reactions

• secrete surfactant
• covers entire alveolar surface and reduces surface tension, preventing their collapse

• left- 3
• right- 4

serous membranes that covers the lungs

serous membranes that line the thoracic cavity

thin, watery, fluid acts as lubricant preventing friction between membranes as lungs inflate/deflate

• inspiration (inhalation)
• expiration (exhalation)

*1 inspiration&1expiration=1 respiration

respiration

• flat (pulling air in flattens it out)
• muscle of diaphragm are contracting
• increases length&vol of thoracic cavity

• domed (dome pushing air up&out)
• muscle of diaphragm are relaxing (dome is resting shape of diaphragm)
• decreases vol of thorax

measures volume of air held in the lungs during the respiratory process

vol of air breathed in or out during respiration at rest

• ERV+IRV+TV
• maximum vol of air that can be inhaled and exhaled

total vol of air that can be voluntarily expired following normal breathing

vol of air remaining in lungs following maximum exhalation

vol of air that can be inhaled, above the tidal volume

• TR+IRV
• vol of air that can be inhaled following quiet respiration

• ERV+RV
• vol of air in lungs after completion of a cycle of quiet respiration

• VC+RV
• total vol of the lungs

• air in pleural cavity
• results in lungs unable to inflate

• pus in pleural cavity
• hemothorax
• prevent expansion of lungs during inspiration

prevent lung inflation as diaphragm will be unable to flatten to increase vol of thoracic cavity

(most common hernia with exception of umbilical hernia)

• associated with heart disease (frequently enlarged heart)
• can also effect functioning of lungs

lower

• conscious: 10-30
• anesthesia: 12-16

• conscious: 20-30
• anesthesia: 12-16

• respiratory reflex
• stretch receptors inhibit inspiration when lungs stretched and stimulate inspiration when deflated

(sitting on couch and take a deep breath out of nowhere)

• in carotid sinus&aortic arch
• monitor degree of stretch of vessels as indicator of BP

• chemoreceptors
• central chemoreceptors- on surface of medulla
• peripheral-in aortic arch&carotid sinus
• stimulated by lowering of pH/fall in oxygen
• results in increase in rate&depth of respiration to eliminate excess CO2

• rising levels of dissolved CO2
• by-product; ketones >acidosis