Test 4 Blood Flashcards
The human circulatory system is subdivided into…
the cardiovascular system
the lymphatic system
is cardiovascular system closed or open?
closed
blood
is the fluid in the vessels of the cardiovascular system…it
transports everything that must be carried from one place to another in
the body.
blood circulation is powered by?
the pumping action of the heart
function of blood?
carries things throughout the body: respiratory gases, nutrients, waste, hormones, cells of the immune system and helps body regulate temperature
The average volume of blood in the body is about…
5-6 L in adult males
4-5 L in adult females
composition of blood
- Classified as a type of connective tissue because
it consists of
cellular and liquid components…
cellular and lliquid components of blood
- A nonliving fluid matrix called the plasma
- Formed elements: Living cells (erythrocytes, leukocytes, and
thrombocytes) suspended in the plasma - NO Fibers (fibrin threads visible when clotting occurs)
spinning blood in a centrifuge
- withdraw blood and place in tube
- centrifuge
- divided to:
- top - Plasma 55% of whole blood
Formed elements
– middle: buffy coat - leukocytes and platelets (
Buffy coat
contains leukocytes and platelets
hematocrit
the percentage of the blood volume that consists of
erythrocytes (averages 45%; males 47% ±5% and females 42% ± 5%
Blood Plasma
• Over 100 different substances are dissolved in suspended in plasma
(90% water): ions, nutrients, gases, hormones, wastes, metabolites,
electrolytes, and proteins
the composition of plasma varies continuously as
cells and
substances are added and/or removed from the blood.
plasma 55%
Water (90% of plasma) Proteins Salts (e.g., sodium, potassium, calcium) Substances being transported (e.g., 02, CO2, nutrients, wastes, hormones)
Cellular elements 45%
RBC
WBC
Platelets
Red Blood Cells
erythrocytes
White Blood cells
Leukocytes
Plateleets
thrombocytes
Plasma contains three main types of proteins
albumin
globulins
fibrinogen
albumin
contributes to plasma
osmotic pressure, which helps keep water
from diffusion out of the blood-stream
into the extracellular matrix of tissues
globulins
include both antibodies
and blood proteins that transport
lipids, iron, and copper.
fibrinogen
functions in clotting
The three types of formed elements present in blood
RBC
WBC
Platelets
function of formed elements in blood cells
-Transport oxygen and a small percentage of carbon dioxide -Part of the body’s nonspecific defenses and the immune system
hemostatis
blood clot formation
Which formed elements is considered true cells and why?
- Only leukocytes are considered true cells
• Neither erythrocytes (which lack nuclei and organelles) nor
platelets (which are cell fragments) are true cells.
most of the blood cells cannot divide, they
they survive in the
bloodstream for only a short time (hours → months) before being
replaced by the division of precursor cells in the bone marrow.
Erythrocytes
Oxygen-transporting cells – 7.5 µm in diameter
-Live 100–120 days and originate in the bone marrow
-Most numerous of the formed elements (females: 4.3–5.2 million
cells/mm3 and Males: 5.2–5.8 million cells/mm3 (~25 trillion total)
-Mature RBCs have no organelles or nuclei…Instead their
cytoplasm is filled with hemoglobin – an oxygen-carrying protein
RBC surface area: volume?
higher
erythrocytes pick up oxygen at?
t the lung capillaries and release it
across other tissue capillaries throughout the body.
erythrocytes special structural characteristics contributes to?
o their respiratory
function
Without organelles and discounting water, RBCs are
e 97%
hemoglobin (Each RBC contains ~280 million hemoglobins!!!)
RBC’s biconcave shape
30% more surface area for rapid diffusion
of oxygen
RBCs generate their energy
anaerobically…thereby conserving any
oxygen they pick up
Leukocytes
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
Leukocytes WBCs
s are the only formed elements that are complete cells,
with the usual organelles and prominent nuclei.
- Less numerous than erythrocytes… 4,800 to 11,000 leukocytes/mm3
Function of Leukocytes
protects the body from infectious microorganism
Leukocytes function outside the
the bloodstream in the loose connective
tissue, where infections occur.
Diapedesis
process of circulating leukocytes leaving the capillaries
The five types of leukocytes are divided into?
two groups based on
the presence or absence of membrane-bound cytoplasmic granules
Granulocytes
Neutrophil
Eosinophil
Basophil
Agranulocytes
Monocyte
Lymphocyte
Neutrophils
-Most numerous WBC (60% of WBCs)
-Nucleus – has two to six interconnected lobes
-Granules contain digestive enzymes that specifically destroy the
cell walls of bacteria
Function of Neutrophils
Phagocytize and destroy bacteria; first line of defense in
an inflammatory response
Eosinophils
- Compose 1–4% of all WBCs
- Nucleus – has two lobes interconnected by a broad band.
- Granules contain digestive enzymes (not specific for bacteria).
Eosinophils Function
Play roles in ending 1) allergic reactions by phagocytosing
allergens and 2) parasitic infections by releasing parasite-digesting
enzymes, esp. in the digestive system
Basophils:
- About 0.5% of all leukocytes = rarest
- Nucleus – usually two lobes
- Weakly phagocytic
Basophils Function
: Granules secrete histamines (function in mediating
inflammation) during allergic responses and parasitic infections
Lymphocytes
- Compose 20–45% of WBCs
- Nucleus – spherical; occupies most of the cell volume
Lymphocytes Function
The most important cells of the immune system; most are
found in lymphoid tissue; effective in fighting infectious organisms;
act against a specific foreign molecule (antigen)
Two main classes of lymphocytes
T Cells
B cells
T cells
(killer T-lymphocytes): attack foreign eukaryotic cells
directly; bind to antigen-bearing cells and punch holes in its
membrane…which triggers apoptosis
B cells
: multiply to become plasma cells that secrete antibodies
(proteins that mark specific antigens for destruction by
macrophages); mostly attack bacteria and bacterial toxins
A third class of lymphocytes
Natural Killer cells: attack cells that lack “self” surface molecules
Monocytes
- Compose 4–8% of WBCs
- The largest leukocytes
- Nucleus – kidney shaped
-Transform into macrophages… phagocytic cells that possess
pseudopods and ingest a wide variety of foreign cells, molecules,
and tiny pieces of debris
Platelets
- thrombocytes
Disc-shaped, plasma membrane-enclosed fragments of cytoplasm
that form by breaking off from larger cells called megakaryocyte
platelets function
: in clotting of blood by adhering to collagen near the edges
of tears in blood vessels and by releasing chemicals that attract
clotting proteins, cause vasoconstriction, and initiate inflammation
Hematopoiesis
the process by which blood cells are formed; begins in the early embryo and continues throughout life
all blood cells originate in
the bone marrow, at a rate of
100 billion new cells a day
Bone marrow
located within all bones
red marrow
actively generates new blood cells; Contains immature erythrocytes; remains in proximal epiphyses of humerus and femur, girdles, and axial skeleton in adulthood
yellow marrow
dormant (makes blood cells only in emergencies); Contains many fat cells and is located in the medullary cavities of long bones of adults
Blood cell formation
Hematopoiesis all originate from?
a blood stem cell…a pluripotential hematopoetic stem cell, which divide continuously and make 2 types of progenitor cells
the two types of progenitor cells
a) Lymphoid stem cells: give
rise to lymphocytes
b) Myeloid stem cells: give
rise to all other blood cells
