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Blood Circulation & Transportation (Blood Pressure (Venous return…
Blood Circulation & Transportation
Function of Circulatory System
Pick up wastes & excreted from the body via lungs @ kidneys
Gas exchange & nutrient-for-waste exchange occur across the walls of the capillaries
Transport oxygen & nutrients such as glucose & amino acids to the cells
Transport heat and transmit force
Circulation
Provide rapid mass transport over distance where diffusion is inadequate @ too slow
Circulation in different types of animals
Invertebrates
With a gastrovascular cavity
Cnidarians; hydra
The cells are either part of an external layer, or they line in the gastrovascular cavity
Each cell is exposed to water and can independently exchange gases, nutrients uptake, and get rid of wastes
Flatworm: planarian
Trilobed gastrovascular cavity branches throughout the small, flattened body
No cell is very far from one of the three digestive branches, so nutrient molecules can diffuse from cell to cell effectively
Open circulatory system
Hemolymph
Mixture of blood & tissue fluid that flows into a body cavity
Carrying nutrients will be pumped by heart via blood vessels into tissue spaces and eventually drained back to the heart
Arthropods & molluscs
Heart pumps hemolymph via vessels into tissue spaces and eventually hemolymph drains back to the heart
Slow delivery of oxygen and nutrients is sufficient for a sluggish animal (clam)
Grasshopper
Colorless blood and doesn’t depend on its open circulatory system to deliver oxygen to its muscles
Tracheae open to outside and take oxygen directly to flight muscles
Contraction of the heart creates negative pressure and draws the blood from the heamocoel into the heart via the ostia
Closed circulatory system
Annelids (earthworm)
Heart pumps blood, which usually consists of cells and plasma, into a system of blood vessels and valves prevent the backward flow of blood
Blood moves into capillaries, for exchanges with tissue fluid
Blood then moves from small veins into the dorsal blood vessel (a vein)
This dorsal blood vessel returns blood to the heart for
re-pumping
Rhythmic pulsatile movements of the heart pump and circulate the blood in the body
Fast circulation with blood retaining in the blood vessels allows blood to be pumped and traveled to far reaching areas of the body part
Blood
Differences between OS & CS
Hemolymph in sinuses surrounding organs
Small branch vessels in each organ
Vertebrates
Single loop
Heart only pumps blood to gills
Fishes
Single atrium and a single ventricle
Blood is fully enriched with oxygen when it leaves gills, the respiratory organ for aquatic organisms
Double loop
2 atria & single ventricle
Amphibians & most reptiles
Single ventricle pumps blood in the pulmonary circuit to the lungs
Pumps blood in the systemic circuit to the rest of the body
Both O2 -rich and O2 -poor blood enter the single ventricle kept separate
O2 -poor blood is pumped out of the ventricle to the lungs before O2-rich blood enters and is pumped to the systemic circuit
2 atria & 2 ventricles
Birds, mammals & some reptiles
Two atria and two ventricles in the heart and the complete separation of the pulmonary and systemic circuits
Right ventricle pumps blood under pressure to the lungs
Left ventricle pumps blood under pressure to the rest of the body
Mammalian cardiovascular system
Four chambers
Septum divides the heart into left and right sides
Right side of heart pumps O2-poor blood to lungs, and the left side pumps O2-rich blood to tissues
Each side has two chambers
Upper, thin-walled chambers are atria
Receive blood
Lower chambers are thick-walled ventricles
Pump blood away from heart
Heart valves
Atrioventricular valves (i.e. tricuspid & mitral valves)- between the atria and ventricles
Semilunar valves (i.e. aortic & pulmonary valves)- between the ventricles and their attached vessels
After the blood passes through the right atrioventricular valve (i.e. tricuspid valve), the right ventricle pumps it through the pulmonary semilunar valve into the pulmonary trunk and pulmonary arteries that take it to the lungs
After the blood passes through the left atrioventricular valve (mitral valve), the left ventricle pumps it through the aortic semilunar valve into the aorta, which takes it to the tissues
Hearbeat is rythmic
The average human heart contracts, or beats, about 70 times a minute, or 2.5 billion times in a lifetime
Cardiac cycle
Atria contract
Ventricles contract
All chambers rest
Systole refers to contraction of the heart chambers, and the word diastole refers to relaxation of these chambers
Phase of a heartbeat
“lub-dub ” sound
Pulse - wave effect that passes down walls of arterial blood vessels following ventricular systole
Rhythmic contraction of heart is due to cardiac conduction system
The SA (sinoatrial) node initiates the heartbeat every 0.85 seconds and is called the cardiac pacemaker
An electrocardiogram is a recording of the electrical changes occur in the heart during cardiac cycle
Blood vessels & its functions
Artery
Carry blood away from the heart to the capillaries
Much thicker wall with elastic tissue that allows arteries to expand and accommodate the sudden increase in blood volume that results after each heartbeat
Smaller arteries branch into a number of arterioles
Capillary
Permit exchange of material with tissues
Extremely narrow (8–10 mm wide) and have thin walls composed of single layer of epithelium with basement membrane
Thin walls of a capillary facilitate capillary exchange
Vein
Venules (small veins) - drain blood from the capillaries; then join to form a vein
Return blood from the capillaries to the heart
Often have valves that allow blood to flow only toward the heart when open and prevent the backward flow of blood when closed
Path of blood in the body
Systemic circuit
Oxygenated blood pumps through out the cells body from the heart
Hepatic portal system
Takes blood from the intestines to the liver
Pulmonary circuit
Deoxygenated blood collected from body cells :arrow_right: Heart :arrow_right: Lungs
Blood Pressure
:arrow_down: as blood flows from aorta to various arteries & arterioles
Blood cannot move back into heart as blood pressure in veins are low
Reading consist of two numbers
Systolic
Due to the blood being forced into the arteries during ventricular systole
Diastolic
The pressure in the arteries during ventricular diastole
Venous return (three factors)
Skeletal muscle contraction
Presence of valves in veins
Respiratory movements
Measured on branchial artery
Cardiovascular Disease
Prevention
Do's
Cholestrol profile
Exercise
Healthy diet
Don't's
Drug abuse
Weight gain
Smoking
Example
Stroke
small cranial arteriole bursts
blocked by an embolus
Heart Attack
coronary artery is completely blocked
Hypertension (High Blood Pressure)
Often seen on people with atherosclerosis
Due to plaque
1)Thrombus - stationary plaque, 2)Embolus- mobile plaque
Blood
Composition
Plasma
Plasma protein (7-8%)
Salts (<1%)
Water (90-92%)
Gases
Nutrients
Hormones
Wastes
Formed Elements
Red blood cells ( 4 million-6 millions)
Transport oxygen using hemoglobin ( Bind loosely with o2)
White blood cells
Neutrophils ( 40-70%)
Engulf
foreign material
Lymphocytes ( 20-45%)
T-cells -attack infected cells that contain viruses
B-cells- Produce antibodies
Antigen -causes the body to produce an antibody to
combine with
Monocytes (4-8%)
transformed into macrophages (performs phagocytosis)
Eosinophils ( 1-4%)
Combating multicelluar parasites and certain infections, they also important mediators of allergy responses and asthma pathogenesis.
Basophils (0-1%)
Contain anti-coagulant heparin which prevents blood from clotting too quickly. They also play a role in both parasitic infections and allergies.
Platelets ( 150k-300k)
Help in blood clotting during injuries
Stem cells
Embryonic stem cells: ability to proliferate to different types of cells
Rich source: Red Bone Marrow
Adult stem cell: differentiate to certain types of cell only
Functions
transport of gases
transport of hormones
transport of excretory products
transport of cells of non-respiratory function
transport of metabolites
transfer of heat
transport of nutrients
transmission of force
Disorder
Haemophilia
Inherited clotting disorder due to the absence of a particular clotting factor, the slightest bump can cause internal bleeding
Types & Donation
B
B antigen, body produces anti-a antibodies to prevent agglutination
AB
Antigen a and b, no antibodies produce to prevent agglutination
A
A antigen, body produce anti-b antibodies to prevent agglutination
O
No antigen, anti-b and anti-a antibodies produced
Rh System and Erythroblastosis Fetalis
Rh System
Rh Factor: Important antigen in matching blood types i
Erythroblastosis Fetalis
Mother produces anti-Rh antibodies, which may cross the placenta and destroy the child’s red blood cells during a subsequent pregnancy
Lympathic system
Functions
Fluid Balance (recycle 10% of blood plasma)
Fat absorption and transportation from the digestive system
Immunological defense
Lymph nodes
Function
Create lymphocytes
Filtering stations
Testing stations
Lymph vessels
Found in all tissues EXCEPT the central neural system, bone marrows, and other tissues without blood vessels
Primary and Secondary lymphoid organs
Primary lymphoid organs
Thymus and bone marrow
production and selection of lymphocytes
Secondary (or peripheral) lymphoid
organs
Sites of lymphocyte activation by antigens
Lymphoid follicles in tonsils, adenoids
Peyer’s patches, spleen, skin, etc.
lymph nodes
Disorder
Elephantiasis
Lymphatic filariasis
Lymphedema