Chapter 10 Blood Flashcards
Cardiovascular system consists of:
- Fluid – blood
- Conducting tubes – blood vessels
- Capillaries
- Arteries
- Veins - Pump – heart
Functions of Blood
- Transports O2, CO2, nutrients, hormones, wastes
- Regulates pH and ion composition by absorbing and neutralizing acids
- Restricts fluid loss at injury sites with clotting process
- Defends against toxins and pathogens with white blood cells and antibodies
- Stabilizes temperature by absorbing heat and distributing blood flow to different areas
Blood
- The only fluid connective tissue in the human body
- Components of blood
1. Formed elements - living cells (RBC, WBC, platelets)
2. Plasma - non-living matrix
Volume in body (~8% of body weight):
5 – 6 liters in average male
4 – 5 liters in average female
Physical Characteristics of Blood
- Blood is a sticky opaque fluid with a salty metal taste
- ~5 x thicker than H2O
- Oxygen-rich blood is scarlet red
- Oxygen-poor blood is dull red/blue
- pH 7.35 – 7.45 (alkaline)
- Blood temperature is slightly higher than body temperature (38°C or 100.4°F)
If blood is centrifuged
- Erythrocytes sink to the bottom Hct ~45%
- Buffy coat in the middle - leukocytes and platelets ~1%
- Plasma rises to the top ~55%
Blood Plasma
- Straw colored fluid – contains over 100 substances (proteins, ions, nutrients, gases, wastes)
- Transports organic and inorganic molecules, formed elements, heat
- Forms ~55% of whole blood volume
- Composed of:
90% water
7% plasma proteins
3% other solutes
blood plasma composed of
90% water
7% plasma proteins
3% other solutes
water
90 % of plasma volume; solvent for carrying other substances, absorbs heat
salt electrolytes
sodium-osmotic balance and pH buffering potassium- regulation of membrane calcium- permeability magnesium chloride bicarbonate
plasma proteins
albumin-osmotic balance and pH buffering
fibrinogen-clotting of blood
globulins- defense ( anti bodies and lipid transport
substances transported by blood
- nutrients
- waste products of metabolism (Urea and uric acid)
- Respiratory gases ( O2 and CO2)
- Hormones (steroids and Thyroid Hormone are carried by plasma proteins)
platelets function
blood clotting
Cell Type: Erythrocytes (red blood cells)
Function: transport O2 and help transport CO2
Cell Type: Leukocytes ( white blood cells)
Function: defense and immunity
Plasma Proteins
- Albumin
- regulates osmotic pressure
- keeps water in the blood stream
- regulates fluid volume (small assistance with pH)
*Clotting proteins/factors (fibrinogen, prothrombin)
helps to prevent blood loss when a blood vessel is injured
- Globulins:
- Antibodies - help protect the body from pathogens
- Lipid carriers - HDL’s and LDL’s
Other Plasma Solutes
*Electrolytes
Na+, K+, Ca2+, Mg2+, Cl–, HCO3–, HPO4–, SO42–
*Organic nutrients
Lipids, carbohydrates, amino acid
*Organic wastes
Urea, uric acid, creatinine, bilirubin, ammonium ions
Formed Elements - RBC
**Erythrocytes (RBCs) - ~45% (37–54%) of whole blood (termed Hematocrit)
-Main function is to carry O2 – also transport some CO2
Red Blood Cells
- RBC count is number of RBCs per microliter (cubic millimeter)
- Males: 4.5–6.3 million per µL
- Females: 4.2–5.5 million per µL
- RBCs make up about 1/3 of all cells in the human body
Functional Aspects of Red Blood Cells
1.Large surface area-to-volume ratio
Oxygen bound to hemoglobin in RBCs
Greater surface area allows for faster exchange of oxygen
- RBCs can form stacks
Allows easier flow through narrow blood vessels without jamming - Flexibility
Can bend and flex to squeeze through capillaries as small as 4 µm (nearly half the normal RBC diameter
Features of Red Blood Cells
*Filled with hemoglobin (Hb):
-Iron-containing protein that binds with oxygen
-Each RBC has ~250 million Hb molecules
14–18 g/dL whole blood in males
12–16 g/dL whole blood in females
Oxyhemoglobin – bright red
Blood with oxygen bound to hemoglobin
Deoxyhemoglobin –dark red / blue
Blood with lots of hemoglobin not bound to oxygen
Red Blood Cell Production and Recycling
-RBCs continually produced and recycled (3 million / sec)
- Short lifespan of 120 days, then:
- Plasma membrane ruptures or cell is engulfed by macrophages
*Broken down in spleen (main site) or liver
Formed Elements -
WBC -White blood cells
Leukocytes (WBCs)
- Crucial in the body’s defense against disease
- Defends the body against bacteria, viruses, parasites, tumors – can move between blood and tissues
- Circulate in bloodstream for short period then migrate into loose and dense connective tissue
Formed Elements
- Attracted to specific chemical stimuli released by damaged tissues
- This positive chemotaxis guides WBCs to pathogens and damaged tissue
- Some (neutrophils, eosinophils, monocytes) are phagocytes
- Surround and destroy the foreign substance by phagocytosis
phagocytes
neutrophils
eosinophils
monocytes
Formed Elements
- When inflammation or infection in the body — the body produces more WBC (normally 5000 – 10000 WBC/µL)
- Can measure WBC in the blood
- High levels (over 11,000) means there is infection or inflammation – increased number is called leukocytosis
- Low levels (called leukopenia) means they are being destroyed – often by drugs (chemotherapy or steroids)
– these low levels puts them at risk for infection
2 Categories of leukocytes
1 . Granulocytes
- Agranulocytes
Granulocytes
- Granules in their cytoplasm
- Include neutrophils, eosinophils, and basophils
Agranulocytes
- Lack cytoplasmic granules
- Include lymphocytes and monocytes (macrophages)
WBCs from most to least abundant
Neutrophils Lymphocytes Monocytes Eosinophils Basophils
Easy way to remember this list
N ever L et M onkeys E at B ananas
Neutrophils (Granulocyte)
- Most common of WBC – 50 to 70%
- Life span ~12 hours
- Role is phagocytosis
- High quantity in exudates
Bad situation to have low levels of neutrophils
- Will not be able to fight infections
- Chemotherapy destroys neutrophils
Basophils (Granulocyte)
- <1% of leukocytes
- Main role is release of histamine to activate inflammation
—Inflammatory chemical that makes blood vessels leaky and leads to chemotaxis
—Reason why you get swelling with inflammation/infection
*Also releases heparin (anticoagulant) – so blood does not clot with all these extra cells
Eosinophils (Granulocyte)
- 2 – 4% of leukocytes
- Secrete chemicals that destroy certain parasites or allergens
- Those with parasite infection or allergic reaction will have elevated eosinophil count
agranulocytes
- Lymphocytes
2. Monocytes
Lymphocytes
- 20–40 % of leukocytes
- Comprised of B-cells and T-cells (part of immune system
Monocytes
- 2–8 % of leukocytes
- Largest of the white blood cells
-Mature into dendritic cells or macrophages
Also eat up old RBCs
Dendritic Cells
Dendritic cells are present in those tissues that are in contact with the external environment, such as theskinand the inner lining of the nose, lungs, stomach and intestines
Function of Dendritic Cells
- as antigen presenting cells (APC).
- act as messengers between theinnateand theadaptive immune systems.
NK (Natural Killer) Cells (3rd type of lymphocyte)
- provide rapid responses to viral-infected cells, acting at around 3 days afterinfection, and respond totumorformation.
- Typically,immune cellsdetectforeign antigens presented on infected cell surfaces, triggeringcytokinerelease, causinglysisorapoptosis.
- unique, as they have the ability to recognize stressed cells in the absence ofantibodiesand foreign antigens, allowing for a much faster immune reaction
Mast Cells (like Basophils
*present in most tissues characteristically surrounding blood vessels and nerves, and are especially prominent near the boundaries between the outside world and the internal milieu, such as theskin and mucosa of therespiratory anddigestive tract.
-
*Contains manygranulesrich inhistamineandheparin.
-Best known for their role inallergyandanaphylaxis
Also play an important protective role, being highly involved in wound healing,angiogenesis,immune tolerance, defense againstpathogens, andbloodbrain barrierfunction.
Formed Elements
Platelets (thrombocytes)
Platelets (thrombocytes)
- Not actually cells – they are fragments of cells
- They cling to broken blood vessel or tissue, thus helping to control blood loss
- Needed for the clotting process
- Low number means more bleeding
- High number means clotting
*Life span of ~9-12 days
DEFINITION OF HEMATOPOIESIS
- blood cell (RBC, WBC, platelets) formation
- Occurs in red bone marrow – common sites include skull, pelvis, ribs, sternum, heads of humerus and femur
Bone marrow
produces different cells at different rates – does this based on the body needs
Erythropoietin (EPO) is :
released into plasma when oxygen levels are low (hypoxia) such as with:
Anemia
Declining blood flow to kidneys
Decreased O2 content of air (ex: high altitudes)
Damage to respiratory surface of lungs
Erythropoietin (EPO)
stimulates stem cells in bone marrow to produce RBCs
Formation of White Blood Cells and Platelets
Controlled by hormones
Controlled by hormones
- Colony stimulating factors (CSFs) and interleukins prompt bone marrow to generate leukocytes
- Role of thymosin in maturation?
- Thrombopoietin stimulates production of platelets
Thrombopoietin
stimulates production of platelets
Blood Clotting Measurements
Partial thromboplastin time(PTT)
Prothrombin time(PT)
International normalized ratio