Bi 067: Review of sectn 7-9 - cardiovascular and lymphatic Heart and Blood vessels: 3 Types of blood vessels: 1. Arteries, arterioles -away from heart, O2 rich 2. Capillaries gas and nutrient/waste exchange 3. Veins, venuoles to the heart, O2 poor Summary table: artery capillary vein Blood pressure Hi Low lowest Valves present or Absent Absent Present absent Wall thickness 3 layer 1 cell 3 layer function Take blood away from heart Exchange of O2/CO2, nutrients/waste Take blood to heart All arteries carry oxygenated blood except: pulmonary artery All veins carry deoxygenated blood except: pulmonary veins Capillaries: the only blood vessels that are small, thin and porous enough to allow exchange of substances with the tissue cells Only certain capillary beds open at a time Ring of muscle controlling flow to capillary beds: precapillary sphincters. Internal environment of cells remain stable because of exchange that occurs between blood and tissue fluid at the capillaries BP and osmotic pressure are forces that control movement of fluid thru capillary walls Arterial end, BP>OP/ midway BP=OP / venous end BP<OP Reminder...Osmotic pressure: a force caused by a difference in solute concentration across a membrane At the arterial end of capillary exchange: BP >OP, water wants to move out, most proteins remain in the blood and red blood cells always remain in the blood. At the venous end of capillary exchange: OP>BP, wastes flow from the cells and enter blood, not all fluid is picked up, haemoglobin is reduced and blood is deep dark red (deoxygenated blood is darker red than oxygenated) Mechanisms that aid with venous blood flow: 1. Skeletal muscle contraction 2. Pressure changes in the thorax due to respiratory movements 3. One way valves in veins
Parts of heart and flow of blood thru heart: Blood going in and out of heart (into an atrium, out of a ventricle) Blood going into the heart (rt atrium) from the superior and inferior vena cava: deoxygenated Blood going into the heart from the pulmonary veins: oxygenated Blood going out of the heart from right atrium to pulmonary artery: deoxygenated Blood going out of the heart (left ventricle) to aorta: oxygenated Oxygenated and deoxygenated blood never mix Valves: Only function of heart valves: prevent backflow Between rt atrium and rt ventricle: tricuspid valve Between lft atrium and lft ventricle: mitral valve Between rt ventricle and pulmonary trunk: pulmonary semi-lunar valve Between lft ventricle and aorta: aortic semi-lunar valve String like structures that anchor the valve leaflets of the AV valve: chordate tendinae
Control of the heartbeat: The 2 sides of the heart are separated by: the septum Systole: working phase includes the contraction of the atrium and ventricles Systole refers to heart muscle contraction Diastole: relaxation phase all chambers relax Highest arterial blood pressure is the: systolic pressure Pressure will be greatest in the aorta during systole Both systolic and diastolic pressure decrease with the distance from the left ventricle Intrinsic (internal) and extrinsic (external) control of HB: Intrinsic control: SA (sinoatrial) node is on the superior dorsal wall of right atrium AV node at the base of the right atrium The AV bundle has 2 branches which travel down to the purkinje fibers Purkinje fibers are found in the lower wall of the ventricles the stimulus that causes the heartbeat conducted in the heart: 1. Electric impulse starts in the SA node found in upper rt wall of atria 2. Both atria contract 3. Impulse then travels to AV node at base of rt atrium 4. Impulse travels down AV bundle to purkinje fibres - ventricles contract from the bottom up Extrinsic control: In cardiac control centre of brain can cause HB to increase for flight or fight, or decrease for normal resting Cardiovascular pathways Pulmonary circuit: Pulmonary arteries go to lungs from heart O2 poor Exchange of gases occurs at lungs 4 Pulmonary veins return from lungs to left atrium of heart O2 rich Systemic circuit Leaves heart through from left ventricle through aorta oxygenated, returns to heart from inferior and superior vena cava, unoxygenated System that begins at intestine and flows through liver and monitors blood: hepatic portal system
Pairing of vessels and locations: 1. Neck and head: carotid artery and jugular vein 2. Shoulder and arm: subclavian artery and vein 3. Heart: coronary arteries and veins/ aorta and vena cava flow to and from heart 4. Digestive tract: mesenteric artery and vein 5. Kidney: renal artery and vein 6. Liver: hepatic portal vein and hepatic vein 7. Hips: iliac artery and vein 8. Legs: femoral artery and vein Cardiovascular system: Blood Name 3 functions of the blood: 1. Transport 2. Defence 3. Regulation Blood transports: waste material, nutrients, gases, hormones, ions, vitamins, proteins...etc Composition of blood: Formed elements: RBC, WBC, Platelets As well as formed elements - Plasma is composed of: water, hormones, gases (CO2 and O2), ions, vitamins, nutrients, wastes, plasma proteins Function of blood platelets: assist in blood clotting All blood cells are made in the red bone marrow All blood cells come from stem cells Stem cells continuously divide producing new blood cells. RBC: Transport O2 and also CO2 (some of the time) They are small and many compared to WBC WBC: Phagocytosis = process of cells ingesting material or cell eating WBC use phagocytosis as one of their ways to defend Lymphocytes: a type of WBC involved in the production of antibodies T and B cells are different types of lymphocyte Antibodies are proteins released by B cells as a defence mechanism of the body
5 different types of WBC and their function: Type neutrophil Basophil Eosinophil Monocyte lymphocyte Some definitions: Function 1 st responders, phagocytotic rxn Allergic rxn response Parasitic worm infection Phagocytotic B cell: antibodies against bacteria antigens T cells: cytotoxic T cells against viruses and cancer Pathogens = microscopic infectious agents such as bacteria and viruses which are capable of causing diseases = any foreign substance that stimulates the immune system Antigen = molecules found on invading pathogens that allow them to be recognized Blood typing: Agglutination = clumping of red blood cells Agglutination happens when incompatible blood type is given Type Antigen Antibody A A B B B A AB A and B none O none both Key is if the antigen exists in the body already, antibodies won t attack it, if it is O and has no antigens it can only receive O because all antigens coming into the body will be attacked, but it can give because antibodies in O will not attack what is already in the recipient/ AB has no antibodies, so no matter what its given, it doesn t have antibodies to attack it Lymphatic system and immunity: Immunity = ability of body to defend itself against infectious agents Lymphatic organs: 1. Red bone marrow - active Red bone marrow in an adult is located: skull, sternum, ribs, pelvic bones, end of long bones. 2. Thymus 3. Spleen 4. Lymph nodes 5. Tonsils 6. Peyers patch 7. Appendix
Immune barriers to entry: Skin Oil glands secrete chemical to kill bacteria on skin Cilia in upper respiratory tract Mucous in upper respiratory tract Local area bacteria in intestine Acidic ph - in stomach acid kills bacteria Non specific defences: 1. Barriers to entry: skin, mucous, oil, stomach acid etc 2. Inflammatory reaction allows phagocytotic cells to enter tissue fluid to attack pathogens 3. Natural killer cells kill by cell to cell contact 4. complement proteins also called =Protective proteins Complement kill foreign microbes by: causing them to burst and help other immune responses Steps of inflammatory response: a. Damaged tissue cells release histamines-histamines cause capillaries to dilate which blood flow which brings extra WBC to area skin red and warm temp can inhibit growth of some pathogens permeability allows proteins + fluids escape from capillaries into tissues swelling and pain b. Blood clotting begins as well c. the arriving neutrophils (Phagocytotic WBC) also squeeze out thru capillary wall and enter tissue fluid and attack pathogens (if lots of neutrophils die off they form yellowy substance called puss) d. usually neutrophils can control and keep infection from spreading - if neutrophils are overwhelmed they realease cytokines that call reinforcements e. cytokines attract other WBC s to area including monocytes which turn into macrophages (and are longer living then neutrophils) that engulf pathogens macrophages can enlist the further help of lymphocytes.
Specific defences: Effective against a particular infectious agent Immune system distinguishes self from nonself Antibodies are proteins released from plasma cells to fight infections B cells: T cells B lymphocytes develop in the bone marrow Represent a specific response Are part of an antibody-mediated immunity Form plasma cells that synthesize and release antibodies or form memory B cells for future Unlike T cells, B cells DO NOT require antigen-presenting cell Require cytokines from Helper T cells in order to undergo clonal expansion Lymphocytes travel to the thymus to become mature T lymphocytes Become helper T cells or cytotoxic T cells or memory T cells Apoptosis =programmed cell death (PCD) once the threat of infection passes development of new plasma cells stop and those present undergo apoptosis because they are no longer needed Comparison of specific immune responses between B cell and T cell immunity: B cell T cell Where produced Red bone marrow Red bone marrow Where mature Red bone marrow Thymus Type of mediated response Antibody cell Antigen recognition B cell receptor recognizes Antigen presenting cells mechanism nonself response Clonal expansion (when cytokines present) forms plasma cells to produce antibodies and memory B cells Clonal expansion into Cytotoxic T cells, helper T cells and memory T cells Acquired immunity Active Long lasting Either produced by own body or induced by vaccines Passive Temporary Individual given prepared antibiotics Antibodies in mother s milk are example of passive immunity