Circulation and Immunity Flashcards
Components of the blood:
Plasma, erythrocytes, leukocytes, platelets
Plasma
55% of blood
90% water
Contains blood proteins, glucose, vitamins, dissolved gases, minerals, waste products of digestion
Plasma proteins help maintain homeostasis
Ex) fibrinogens: blood clotting
Erythrocytes
Red blood cells
transports oxygen in hemoglobin
hemoglobin
iron containing pigment
Each Hb molecule can carry four oxygen molecules
red blood cell structure
RBCs have a biconcave shape = concave on both sides
-increases surface area for gas exchange
RBCs have no nucleus = e nucleated
-enables the cell to carry more hemoglobin
Anemia
Lack of iron in diet, or lack of processing of iron into hemoglobin
Can be treated with iron supplements
erythropoiesis
The formation of red blood cells in blood-forming tissue.
bone marrow is the cite of RBC reproduction
RBC’s begin as stem cells and contain a nucleus : divide – shrink- nucleus disappears – discharge into blood
immature RBC’s can undergo mitosis (have nucleus)
mature RBC’s cannot undergo mitosis (no nucleus)
erythropoietin
there is less oxygen available so the body compensates by creating more RBCs
a hormone called erythropoietin is produced by the kidneys and stimulates red blood cell production.
blood doping
Storing your own red blood cells for donation before sporting events
Increases oxygen carrying capacity
Also can use EPO (erythropoietin) as an injection
Difficult to catch
Leukocytes
white blood cells
less numerous than RBCs
have a nucleus
some are phagocytes: engulf foreign cells, release an enzyme that digests the invader
-remaining fragments are pus
platelets
initiate clotting, form a platelet plug at site of a cut
platelets break apart and release a protein called thromboplastin (one of many clotting factors)
fibrin
Clotting factors + calcium ions react to form fibrin- threads which seal the cut
glycoproteins
markers located on the membrane of some of the RBC’s
antigen
Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body.
agglutinate
antibodies attach to antigens and cause the blood to clump or agglutinate
agglutinated blood can no longer pass through the capillaries and clogs the tissues preventing oxygen and nutrient delivery
Rhesus Factor
the rhesus factor is another antigen on the RBC
if you have the rhesus factor you are said to be Rh+ (85% of Canadians)
positive blood type
no antigen = Rh -
blood types
a, b, ab, o
blood type AB+ is the universal acceptor (can accept all blood types)
blood type O- is the universal donor (can be given to anyone but can only accept O)
Erythroblastosis fetalis
a rare pregnancy complication that occurs when a pregnant person’s immune system attacks the fetus’s red blood cells.
Concern when mom is Rh- and baby is Rh+
first pregnancy there is no problem
During birth, the blood of the child and mom mixes
now mom makes antibodies against Rh+
second pregnancy : if embryo is Rh+, the antibodies may diffuse across the placenta and destroy the embryo’s red blood cells
treatments for Erythroblastosis fetalis
- transfusions of Rh- blood
- injections to inhibit the formation of antibodies against Rh+ antigens
Immune Response
The body’s first line of defense is physical: skin, mucus, stomach acid
The second line of defense is utilized when invaders (antigens) take up residence within the body
phagocytosis
process by which certain living cells called phagocytes ingest or engulf other cells or particles.
ex) macrophage
types of leukocytes (white blood cells)
macrophage- phagocytosis
lymphocytes-T and B cells
T cells
produced in the bone marrow, stored in the thymus gland
seeks out the intruder and signals the attack
B cells
produce the chemical weapon: antibodies
released from bone marrow
Antibodies are “Y” shaped
they are specific and connect to a certain antigen “lock and key”
Antibodies that attach themselves to the antigen alter their shape and prevent access to the entry ports of cells
antibodies
proteins that protect you when an unwanted substance enters your body.
Steps to an immune attack
- Bacteria or virus –the antigen- enters the body
- A macrophage engulfs the invader and pushes its antigen markers outside of the membrane
- Helper T cells recognize the harmful markers and signal the B cells
- B cells release antibodies which attach to the antigen
- Killer T cells now recognize the foreign cell and destroy it
- The battle has been won so Suppressor T cells shut down the response
- Memory T cells are made so the body can quickly identify the antigen should it return (immunity)
Allergies
body mistakes harmless cells for harmful invaders
Autoimmune disease
body attacks itself
ex) rheumatoid arthritis
vaccines
developed by Edward Jenner
a weakened microbe is injected into a person. The immune systems creates antibodies against that disease
Antibiotics
antibiotics are special chemical agents usually obtained from living organisms
they kill bacteria in your body but do not create immunity
