Blood and Circulatory System Flashcards
blood function overview
- circulates to maintain relative constant environment for all cells
1. carries nutrients and oxygen to tissues 2. carries carbon dioxide from tissues to lungs 3. carries waste products from tissues to kidneys for excretion 4. carries hormones 5. temperature control by transporting heat from deeper structures to surface of body 6. water balance 7. buffers like bicarbonate maintain constant pH 8. clotting prevents excess blood loss from injury 9. contains factors for defense against disease
formed elements of blood
rbc, wbc, blood platelets
rbc and platelets lack nuclei
Red blood cells/erythrocytes
biconcave discs, the shape allows for large surface area for oxygen exchange
presence of hemoglobin within the RBC allows transport of oxygen and red colour
Hemoglobin
organic compound made of 4 red porphyrin pigments called memes, each containing an atom of iron and globin, which consists of 4 amino acid chains (hemoglobin=Hb)
iron metabolism
iron is lost through feces, urine, and sweat, as well as during fetus development, nursing, and menstruation
methemoglobin
true oxidation product of Hb that is unable to transport oxygen because the iron is in the ferric state, not ferrous
methemogloniemia
nitrites and chlorates with methemoglobin cause nitrate poisoning from fertilizer and chlorate poisoning from weed killers in cattle
carboxyhemoglobin
stable compound formed when carbon monoxide, present in exhaust fumes, combines with Hb
-affinity for Hb for CO is 210 times greater than its affinity for O2
Carboxyhemoglobin is unable to carry oxygen and the individual dies of suffocation
cyanide poisoning
produces suffication by interfering with the utilization of oxygen by tissues
- has NO effect on oxygen carrying ability of blood
- may occur when cattle each stunted or frosted grain sorfhums
methylene blue
used to treat cyanide poisoning by forming methemoglobin in blood, reacting with cyanide to form cyanmethemoglobin, an inactive compound that is slowly degraded and detoxified by body
RBC formation
in adults it occurs in bone marrow, also producing granular leukocytes
in fetus the liver, spleen, and lymph nodes produce RBC
destruction of RBC occurs after 3 to 4 months in circulation
RBC disintegrates, releasing Hb into blood and broken cell debris is removed from circulation by macrophages
Fate of Hemoglobin
Hemoglobin is converted bilirubin and then further to urobulin, which gives urine it’s yellow colour
Jaundice or Icterus
when bilirubin accumulates in blood it results in a condition in liver and intestines, causing a mucous membrane that makes mouth and eyes appear yellow
caused by liver damage, occlusion of bile ducts, or by destructive blood diseases
Hemolysis
breakdown of RBC so Hb escapes into the plasma
caused by bacterial toxins, snake vemons, blood parasites, hypotonic solutions, and many chemicals
-the resulting Hb in plasma gives it a reddish colour, a condition known as hemoglobinemia
Hb excreted in urine is known as hemoglobinurea
hemaglutination
clumping of RBC, usually when cells of one species are transffered to another, or when given the wrong blood type to humans or horses
Normal values of blood pressure
systolic: 90-120, dystolic: 60-80
Anemia
results if either the number of functional RBC or the quantity of Hb is decreased far below normal levels; leads to heart failure
- may be caused by deficient blood formation from poor nutrition and deficiency of iron, copper, and vitamins
- loss of blood due to hemorrhage from wounds or because of parasites such as stomach worms or lice
- deficient secretion of intrinsic factor from stomach necessary for vitamin B absorption
- hemolysis or immature RBC
Platelets/thrombocytes
fragments of megakaryocytes: larges cells formed in bone marrow
surrounded by plasma membrane and contain microtubules, lysosomes, mitochondria, and golgi vesicles, but not nuclei
important for blood clotting and reducing blood loss
platelet/thrombocytes process
adhering to vessel walls and each other at site of injury, they form a plug that occlludes the opening
also release serotonin that cause local constriction of injured vessels
Leukocytes/WBC
nucleated and capable of independent movement
subtypes: Granulocytes and Agranulocytes
-gran. last hours, monocytes months, and lymphocytes years
non-functional in blood stream and are transported to tissues when needed
granulocytes
contain granules within cytoplasm that stain with wrights stain
subtypes: neutrophils, eosinophils, basophils; formed in red bone marrow
eosinophils (acidophils)
stained red with acid dye eosin
increase in number during CHRONIC infection
amoeboid and phagocytic
function: detoxify foreign proteins introduced via lungs, GI tract, or toxins made by bacteria and parasites
-number increase in allergic reactions
basophils
stained with methylene blue, contains heparin preventing clotting
contain histamine, badykinin and serotonin
-are also the mast cells present in conn. tissue
neutrophils
- stained diff, neither red nor blue
- first defense against infection by migrating to bacteria, pass through blood wall and engulf and destroy bacteria
- while destroying bacteria, neutrophils also degrade dead tissue in area, resulting in PUS
- localized accumulation of pus is called an ABSCESS
- increase of neutrophils present during infection
tissue injury, neutrophils, and phagocytosis
autolysis of gran. leads to lysosomal enzymes that act on surrounding tissue, releasing chems that attract neutrophils
injured tissue=release histamine=inflammation
histamine increases blood flow, causes redness and inflammation
dilation of capillaries: more proteins and fluid leak out, more fibrinogen leaks out, coagulation quicker and barrier against spread of infection quicker
Neutrophilia
inflamed tissue release leukopoietic factor, acts on marrow, releasing more neutrophils and increases rate of granulocyte formation
increased number of neutrophils is neutrophilia, and occurs during bac. infection, cancer, metabolic poisoning, hemorrhage, and exercise
Agranulocytes
few granules,
subtypes include monocytes and lymphocytes
monocytes
largest WBC
- phagocytic and used for less acute infections, ie. tuberculosis
- when monocytes from from blood enter tissues, they develop into large phagocytes called MACROPHAGES
lymphocytes
variable in size and appearance; large nucleus surrounded by small cytoplasm
function: to respond to antigens (foreign substances) by forming ANTIBODIES that circulate blood or in development of cellular immunity
hematopoeisis
formation of blood cells, divided into three lineages:
erythroid: RBC, lymphopoeisis, for lymphocytes, developed to T-cells from thymus or B cells from Bone marrow
and Myelocytes, which develop into granuloctyes, megakaryocytes (platelets), and macrophages/monocytes
all originate as haematopoietic stem cells in bone marrow
Plasma
- fluid portion of blood
- bathes aall cells of body and protects them from external influences
- made up of 82% water and balance 8% other substances
- kidneys are responsible for maintaining constant portions of water and other substances, which include proteins, glucose, lipids, amino acids, hormones, sodium chloride, inorganic mineral salts, urea, uric acid, and creatinine
Plasma Proteins: Globulins
alpha and beta globulins synthd in liver, gamma by lymphocytes; most antibodies therefore are gamma
fibrinogen is a beta globulin synthed in liver and is important for clotting in platelets
Plasma Proteins: albumin
abundant protein in blood
produced by liver and important for binding and transport of many substances in blood
-responsible for 80% of total osmotic pressure of the plasma
functions of plasma proteins
carriers: many p. proteins solubilize substances like hormones and iron to be carried
immunity functions: ie gamma globulin
buffering functions: plasma proteins help to prevent great changes in pH of blood like other blood buffers such as bicarbonates, sulfates, and phosphates
Maintenance of osmotic pressure
lymph
fluid of lymphatic system, which brings bacteria to lymph nodes for destruction
-derived from interstitial fluid, and changes as blood exchanges substances with interstitial fluid
Circulatory system
consists of heart and system of vessels for circulation
vessel carrying blood away from heart are arteries
vessels carrying to heart are veins
vessels carrying lymph or tissue fluid are lymphatics
Heart
coneshaped hollow muscular structure
- base is attached to other thoracic structures by large arteries, veins, and pericardial sac
- consists of three layers: epicardium, moycardium, and endocardium
atriums and ventricles
atriums receive blood from veins, ventricles send blood to arteries; betweeen them is the atrioventicular valve
left AV valve: bicuspid valve
right AV: tricuspid
chordae tendinae
valves are attached to ventricular wall by means of these fibrous cords
other valves:
aortic semilunar valve: btw ventricle and aorta
pulmoarysemilunar valve: btw ventricle and pulmonary artery
first branches of aorta go to…
the heart, through the right and left coronary arteries
coronary thrombosis
aka heart attack, refers to a clot in coronary artery or one of its branches, causing lack of oxygen and nutrients to heart and severe tissue damage
-most blood returns to right atrium from coronary veins, some empties directly into the chamber through heart wall
thoracic aorta and its branches
bronchials, esophagus, lymph glands and abdomin
brachiocephalic trunk
supplies right arm, head, and neck and is the first branch of the aortic arch, separates into the subcalvian and and carotid arteries
abdominal aorta
largest artery in abdominal cavity and is direct continuation of descending artery
portal circulation
arrangement in which a vessel breaks up into capillaries and then recombines again to form another vessel is known as a portal system
hopothalmo-hypophyseal portal circulation
releases hormones
renal portal circulation
in birds, reptiles, and amphibians, part of the blood returning from the hind limbs enters the kidneys to form the real portal system
hepatic portal circulation
blood brained from the stomach, spleen, intestines, and pancreas is filtered through the liver by hepatic portal system before re-entering the general circulation
-allows liver to modify ad store nutrients for future use and to detoxify any harmful substances that may otherwise be absorbed in digestive tract
Fetal circulation
- Umbilical VEIN brings pureblood from the placenta to the liver and heart, the latter via the DUCTUS VENOSUS
- FORAMEN OVALE allows blood to mix between left and atrium/auricle, so both ventricles can pump blood to body
- DUCTUS ARTERIOUSUS allows blood from right ventricle to bypass the lungs and also supply the body
- UMBILICAL ARTERIES allow blood to return to the placenta to be oxygenated
lymphatic system
includes both lymphoid tissue of body and lymphatic vessels associated with lymphoid tissue
functions: drains tissue fluid into blood system
- forms antibodies and acts as a defense mechanism against noxious materials by filtering them out of the tissue fluid and phagocytizing them
- lymphoid tissue consists of accumulation of lymphocytes trapped in spaces between fibers of conn. tissue or intestines
lymph nodes
lymphoid tissue may be scattered in some organs, or accumulated as nodes or to form special organs like tonsils , thymus, and spleen
nodes are glands that act as filters for lymph
lymphatic vessels and lacteals
vessels carry lymph through one way channel and drain into the posterior vena cava
lacteals are a special group of lymph vessels that drain into the instestinal wall, which absorb lipids from the intestines in the form of Chyle
lymphocytes (regarding lymph and cancer)
are plasma cells, and the source of antibodies
- cancer and infections may spread through lymph channels
- when tumors are removed, it is best to remove all the lymph nodes draining the cancerous area
spleen
lymphatic gland, stores blood
- part of macrophage system
- phagocytizes fragile, worn out RBC
cardiac cycle
sequence of events that occur during one complete cycle
diastole
relaxation of the chamber of heart just prior to and during filling
systole
contraction of a chamber of the heart in process of emptying
heart sounds
lub=closure of AV valves at time of contraction of muscle fibers of ventricles; it is louder, lower pitch, and longer than second sound
dub=produced by vibrations of vessel walls, blood columns, and closed semilunar valves
conducting system of heart: SA node
sino-atrial node is the origin of the heart beat, and thus called the pacemaker
impulses spread through the atria causing them to contract in atrial systole
heart block
any interruption of the SA node impulse pathway
control of the heart rate is done by
parasympathetic nervous system
atrioventricular node
av node set off by sa node, causes ventricles to contract
blood quantity and weight
40L in cows, 5-6L in humans, 7% of total weight
blood pressure
pressure blood exerts against the vessel walls
systollic pressure
produced by contraction of the ventricles of the heart
diastolic pressure
pressure exerted by the elastic walls of the arteries while the ventricles relax
pulse
wave of SYSTOLIC pressure, starting at heart and throughout the arterial network
shock
when effective volume of blood is insufficient to supply needed nutrition to body tissues and to remove waste
lack of blood may be due to hemorrhage, dilation of viscera vessels, loss of fluid in tissue, failure of blood to return to heart, or failure of heart to pump
anaphylactic shock=causes vasocontriction and closing of throat
factors contributing to arterial blood pressure: peripheral resistance
caused by ARTERIOLAR TONE, due to sympathetic constrictor activity, and VISCOSITY of BLOOD due to packed cell volume
Systolic electrocardiogram
P= spread of electrical activity to SA node QRS= spread of electrical activity from AV node to ventricles; aka depolarization or "Lub" T= repolarization of ventricles or "Dub"
arterial pressure: cardiac output
STROKE VOLUME due to amount of blood returning to heart and HEART rate, conducted by vagus tone
-both controlled by sympathetic activity
Blood coagulation factors
- fibrinogen
- prothrombin
- thromboplastin
- Christmas Factor
- fibrin stabilizing factor
clot-preventing factor
Heparin
