10.2 Blood Flashcards
What is the blood’s transport function?
transports nutrients, wastes, and hormones
What is the blood’s regulatory functions?
- helps regulate body temperature by dispersing body heat
- helps regulate blood pressure because the plasma proteins contribute to the osmotic pressure of blood
What is the blood’s protective functions?
- helps protect the body against invasion by disease causing pathogens
- clotting mechanisms
What do buffers in blood do?
help maintain blood pH at about 7.4
What do clotting mechanisms in the blood do?
protect against potentially life-threatening loss of blood
When does blood separate into 3 layers?
if blood is collected from a person’s vein into a test tube and prevented from clotting and then centrifuged
What is the upper layer of blood?
plasma: the liquid portion of the blood
What is the middle layer of blood?
white blood cells and platelets
What is the bottom layer of blood?
red blood cells
What is the middle and bottom layer of blood together?
the “formed elements”
leukocytes and platelets, <1% of whole blood
(erythrocytes, about 45% of whole blood)
What are the components of plasma?
- water: 90-92%
- plasma proteins: 7-8%
- salts: less than 1%
- gases
- nutrients
- nitrogenous wastes
- other (ie. hormones, vitamins)
What is the function and source of water in the plasma?
function:
- maintains blood volume
- transports molecules
source: absorbed from intestine
What is the function of plasma proteins in the plasma?
- maintain blood osmotic pressure and pH
- assist in transporting large organic molecules in blood
What are the 3 main plasma proteins in plasma?
albumin, antibodies, fibrinogen
What is the function and source of albumin in the plasma?
function:
- maintains blood volume and pressure
- transports bilirubin
source: liver
What is the function and source of antibodies in the plasma?
function: fight infection
source: B lymphocytes
ie. immunoglobulins
What is the function and source of fibrinogen in the plasma?
function: blood clotting
source: liver
What is bilirubin?
a breakdown product of hemoglobin
What do lipoproteins do in the plasma?
plasma proteins that transport cholesterol
Why do plasma proteins maintain blood volume?
they are too large to leave the capillaries
therefore, blood in capillaries normally has a higher solute concentration than does tissue fluid, and water automatically diffuses into them
Where are red blood cells continuously manufactured?
in the red bone marrow of the skull, ribs, vertebrae, and ends of long bones
How many red blood cells are there in the body?
4-6 million per mm^3 of whole blood
Describe mature red blood cells (2).
- no nucleus
- biconcave disk
What does the shape of the red blood cell do?
- increases their flexibility for moving through capillary beds
- increases their surface area for diffusion of gases
Why do red blood cells carry oxygen?
because they contain hemoglobin, the respiratory pigment responsible for the red colour of cells
Describe the structure of hemoglobin.
- 4 polypeptide chains
- each chain is associated with heme, a complex iron-containing group
What does the iron portion of hemoglobin do?
iron portion of hemoglobin acquires oxygen in the lungs and gives it up in the tissues
What is the function and source of salts in the plasma?
function:
- maintain blood osmotic pressure and pH
- aid metabolism
source: absorbed from intestine
What are the 2 gases in plasma?
oxygen and carbon dioxide
What is the function and source of oxygen in the plasma?
function: cellular respiration
source: lungs
What is the function and source of carbon dioxide in the plasma?
function: end product of metabolism
source: tissues
What are the 3 nutrients in the plasma?
lipids, glucose, amino acids
What is the function and source of nutrients in the plasma?
function: food for cells
source: absorbed from intestine
What are 2 nitrogenous wastes in the plasma?
urea and uric acid
What is the function and source of nitrogenous wastes in the plasma?
function: excretion by kidneys
source: liver
Name 2 “other” contents in the plasma.
hormones and vitamins
What is the function and source of hormones and vitamins in the plasma?
function: aid metabolism
source: varied
Why do red blood cells only live around 120 days?
possibly because they lack nuclei
Where are red blood cells destroyed?
mainly in the liver and the spleen, where they are engulfed by large phagocytic cells
What happens to the iron when red blood cells are destroyed?
- mostly salvaged or reused
- heme portion undergoes chemical degradation, and the liver excretes it into the bile as bile pigments
What is anemia?
when the body has an inefficient number of red blood cells or the red blood cells do not contain enough hemoglobin
What are the 3 basic causes of anemia?
- decreased production of red blood cells
- loss of red blood cells from the body
- destruction of red blood cells within the body
What happens in iron-defficiency anemia (most common type)?
red blood cell production is decreased, most often due to a diet that does not contain enough iron
What happens in chronic anemia?
when arterial blood carries a reduced amount of oxygen
What happens when someone suffers chronic anemia or takes up residence at a high altitude?
the kidneys increase their production of hormones called erythropoietin
What does the hormone erythropoietin do?
speeds the maturation of red blood cells in the bone marrow
What is the source of red blood cells, white blood cells, and platelets?
red bone marrow
Red Blood Cells
- function
- description (size, shape + nuclei)
function:
- transports oxygen
- helps transport carbon dioxide
description:
- 7-8 micrometers in diameter
- bright-red to dark-purple biconcave disks without nuclei
How many white blood cells are in the body?
5000-11000 per mm^3 of blood
What do white blood cells do?
- fight infection
- role in the development of immunity
What are the 3 types of granular leukocytes (wbc)?
neutrophils
eosinophils
basophils
What are the 2 types of agranular leukocytes (wbc)?
lymphocytes
monocytes
What are the 2 types of white blood cells?
granular and agranular
Describe neutrophils.
- % of wbc
- size
- cell shape and nucleus lobes
- granules in cytoplasm
- what do they phagocytize?
- 40-70% of wbc
- 10-14 micrometers in diameter
- spherical cells with multilobed nuclei joined by nuclear threads
- fine, pink granules in cytoplasm
- phagocytize and digest pathogens
Describe eosinophils.
- % of wbc
- size
- cell shape and nucleus lobes
- granules in cytoplasm
- what do they phagocytize?
- 1-4% of wbc
- 10-14 micrometers in diameter
- spherical cells with bilobed nuclei
- coarse, deep-red, uniformly sized granules in cytoplasm
- phagocytize antigen 1/N antibody complexes and allergens
Describe basophils.
- % of wbc
- size
- cell shape and nucleus lobes
- granules in cytoplasm
- releases?
- 0-1% of wbc
- 10-12 micrometers in diameter
- spherical cells with lobed nuclei
- large, irregularly shaped, deep-blue granules in cytoplasm
- releases histamine, which can cause inflammation
What does histamine do?
promotes blood flow to injured tissues
Describe lymphocytes.
- % of wbc
- size
- cell shape and nuclei description
- responsible for?
- 20-45% of wbc
- 5-17 (average 9-10) micrometers in diameter
- spherical cells with large, round nuclei
- responsible for specific immunity
Describe monocytes.
- % of wbc
- size
- cell shape and nucleus lobes
- what do they become and do?
- 4-8% of wbc
- 10-24 micrometers in diameter
- large spherical cells with kidney-shaped, round, or lobed nuclei
- become macrophages that phagocytize pathogens and cellular debris
How many platelets are in the body?
150,000-300,000 per mm^3 of blood
Platelets
- function
- description (size, shape + nuclei, granules)
function: aid clotting
description:
- 2-4 micrometers in diameter
- disk-shaped cell fragments with no nuclei
- purple granules in cytoplasm
How do white blood cells differ from red blood cells?
- larger
- have a nucleus
- lack hemoglobin
- appear translucent without staining
What are monocyte-derived macrophages and what do they do?
- the body’s scavengers
- engulf microbes and debris in the body’s fluid and tissues
- in liver, kidney, spleen
What are granular leukocytes?
filled with spheres that contain enzymes and proteins, which help white blood cells defend the body against microbes
What do monocytes differentiate into?
phagocytic dendritic cells and macrophages
What are dendritic cells?
- present in tissues that are in contact with the environment (skin, nose, lungs, intestines)
- once they capture a microbe with their long, spiky arms called dendrites, they stimulate other white blood cells to defend the body
What are the 2 types of lymphocytes and what do they do?
B lymphocytes (B cells): produce antibodies
T lymphocytes (T cells):
- helper T cells: regulate the responses of other cells
- cytotoxic T cells: able to kill other cells
How can you indicate if disease is present?
if the number of any type of white blood cell increases or decreases beyond normal
ie. neutrophil numbers tend to increase in response to different bacterial infections
What is infectious mononucleosis?
- caused by the Epstein-Barr virus
- often has increased number of B cells
What is AIDS?
having an abnormally low number of T cells
What is leukemia?
a form of cancer characterized by uncontrolled production of abnormal white blood cells
How long do white blood cells live?
many live only a few days or may die combatting pathogens, others lives for months or even years
What do platelets (thrombocytes) result from?
fragmentation of certain large cells called megakaryocytes in the red bone marrow
What is the rate at which platelets are produced?
200 billion a day
What is fibrinogen and prothrombin?
proteins manufactured by the liver
What is Vitamin K?
- found in green vegetables
- formed by intestinal bacteria
- needed for prothrombin production
- deficiency can result in clotting disorders
Describe the 4 steps of the blood-clotting process.
- blood vessel is punctured
- platelets clump at the site of the puncture and partially seal the leak
- platelets and damaged tissue cells release prothrombin activator, which converts the plasma protein prothrombin to thrombin
- this requires calcium ions
- thrombin then acts as an enzyme that severs the two short amino acid chains from each fibrinogen molecule, activating it - the activated fragments then join end to end, forming long threads of fibrin and traps the red blood cells
- these cells make a clot appear red
What do fibrin threads do?
wind around the platelet plug in the damaged area of the blood vessel and provide the framework for the clot
Why is a fibrin clot only temporary?
as soon as blood vessel repair is initiated, an enzyme called plasmin destroys the fibrin network and restores the fluidity of the plasma
How can you inhibit the clotting process?
with medications such as heparin
What is serum?
- a yellowish fluid developed above the clotted material if blood is allowed to clot in a test tube
- contains all the components of plasma except fibrinogen
What is hemophilia?
a group of inherited clotting disorders caused by a deficiency in a clotting factor
What is the most common type of hemophilia?
hemophilia A, accounts for 90% of all cases
What is hemophilia A?
- almost always occurs in males because the faulty gene is found on the X chromosome (females have two X’s therefore they have a backup copy of the gene)
- slightest bump to an affected person can cause bleeding into the joints
- cartilage degeneration in the joints and resorption of underlying bone can follow
- bleeding into the muscles can lead to nerve damage and muscular atrophy
- death can result from bleeding into the brain with accompanying neurological damage
- people with hemophilia often usually require frequent blood transfusions, although they may also be treated with injections of the specific clotting factor the are lacking
What is a stem cell?
a cell that is ever capable of dividing and producing new cells that go on to differentiate into particular types of cells
What can multipotent stem cells do? Where can you find them?
they have the potential to give rise to other stem cells for the various formed elements
ie. can be found in bone marrow
What can bone marrow stem cells differentiate into?
other types of cells including liver, bone, fat, cartilage, heart, and even neurons
What do bone marrow stem cells have the possibility of treating?
diabetes, heart disease, liver disease, brain disorders (ie. Alzheimer’s or Parkinson’s)
What happened in a research in which the brains of women received bone marrow stem cells from male donors as part of treatment for leukemia?
all recipients had neurons in their brains that contained Y chromosomes
some of the bone marrow stem cells derived from male donors had travelled to the brain, where they differentiated into neurons
Among all the various types of adult stem cells in the body, why are bone marrow stem cells particularly attractive?
they are the most accessible
Why do some researches prefer to work with embryonic stem cells?
they think they are more likely to become any type of cell
Why are embryonic stems available?
many early-stage embryos remain unused in fertility clinics, although this issue has become controversial
Where are stem cells also now collected today?
from umbilical cord blood for possible future treatments
What is the composition of blood?
formed elements and plasma
What is the composition of plasma?
liquid portion of blood
What is the composition of serum?
plasma minus fibrinogen
What is the composition of tissue fluid?
plasma minus most proteins
What is the composition of lymph?
tissue fluid within lymphatic vessels
What are the 2 forces that primarily control movement of fluid though the capillary wall?
- osmotic pressure, created by salts and plasma proteins, which tends to cause water to move from the tissue fluid to the blood
- blood pressure, which tends to cause water to move in the opposite direction
Why does water exit a capillary at the arterial end?
blood pressure is higher than the osmotic pressure of blood
Where is blood pressure lower in the capillary?
midway along the capillary
What happens midway along the capillary?
the 2 forces essentially cancel each other, and there is no net movement of water
solutes now diffuse according to their concentration gradient
- nutrients (glucose, amino acids) and oxygen diffuse out of the capillary
- wastes diffuse into the capillary
What happens in the pulmonary circuit when the 2 forces cancel each other?
the movement of these gases is reversed
Describe the pulmonary circuit.
- oxygen concentration is higher in the lung tissues
- carbon dioxide concentration is lower
What remains in the capillaries and what leaves
red blood cells and almost all plasma proteins remain
small substances leave that contributes to tissue fluid
What is tissue fluid (interstitial fluid)?
fluid between the body’s cells that tends to contain all the components of plasma but lesser amounts of protein, which generally stay in the capillaries
What happens at the venous end of the capillary?
- blood pressure has fallen even more
- osmotic pressure is greater than blood pressure
- water tends to move into the capillary
How much fluid that leaves the capillaries returns?
almost the same amount of fluid that left the capillaries returns to it, although some excess tissue is always collected by the lymphatic capillaries
What do lymphatic capillaries do?
collect excess tissue fluid and become lymph
What is lymph?
tissue fluid contained within lymphatic vessels
Where is lymph returned to?
systemic venous blood
When is lymph returned?
when the major lymphatic vessels enter the subclavian veins in the shoulder region
