Download Lecture 19: Blood

Lecture 19: Blood
M/O Chapter 21
91. Describe the function and composition of blood.
92. List the five types of leukocytes in order of their relative prevalence in normal blood and classify each
type as a granulocyte or agranulocyte.
Blood
Blood is a fluid connective tissue in the “special hematopoetic” category.
1. Functions:
A. Transports stuff throughout the body
i. Gasses (carbon dioxide and oxygen)
ii. Nutrients (sugars, amino acids, fats, etc)
iii. Hormones (which help regulate body processes)
B. Plays a role in homeostasis of:
i. body temperature
ii. blood pressure
iii. pH
iv. concentrations of various substances in body fluids
C. Is involved in protection and immunity
i. White blood cells are players in the immune system
ii. Platelets are involved in blood clotting
2. You have about 5 L of blood (in 70 kg man…) which is equal to about 10.5 pints.
A. Plasma: Fluid portion of blood (3 L)
i. 92% water,
ii. 7 % plasma proteins
a. Fibrinogen (clotting)
b. Albumins (which create osmotic pressure)
c. Globulins (which can include antibodies, enzymes, and transport proteins)
iii. 1 % other dissolved stuff (AA, glucose, lipid, O2, vitamins, etc)
iv. Identical to interstitial fluid, except for plasma proteins
a. Increases the osmotic pressure in the blood, drawing water from the interstitial fluid into the blood
b. The liver makes most of the plasma proteins
3. Cellular (formed) elements: (2 L)
A. All blood cells descend from pluripotent hematopoietic stem cell in bone marrow…
i. RBC (erythrocytes)- carry gases for the respiratory system
ii. WBC (leukocytes) – are part of the immune system
iii. Platelets (thrombocytes) – tiny little cell fragments responsible for clotting
a. Born from exploded parts of megakaryocytes as they try to squeeze into the blood stream
4. Clinical relevance
A. Hematocrit
B. Cell differential count (CDC)
5. If you centrifuge whole blood, this is what it will look like:
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Leukocytes (WBC)
Granulocytes
1. Neutrophils
A. Abundance: Most abundant WBC (60-70%)
B. Function: Phagocytic, especially bacteria
C. Lifespan: 1-2 days, and ingest 5-20 bacteria in that time
D. Location: Most stay in the blood
E. Identifying features: Unstained cytoplasm and multilobular nucleus
F. Other facts: Release cytokines (including PYROGENS, which cause fever)
2. Eosinophils
A. Abundance: 2-4% of all blood cells in circulation
B. Function: Phagocytic, especially allergens and parasites
C. Lifespan: 6-12 hrs
D. Identifying features: Granules are reddish orange; dumbbell shaped nucleus
E. Other facts: Release cytokines (including PYROGENS, which cause fever)
3. Basophils (in circulation) Mast cells (in tissue)
A. Abundance: 1%
B. Function: Releases inflammatory mediators (contained in their granules), such as:
i. histamine (a vasodilator and inflammatory agent)
ii. heparin (an anticoagulant that keeps blood flowing)
iii. This results in blood flowing and flushing an area and these play a major role in anaphylactic shock.
C. Identifying features: They are full of dark purple granules...so many that the nucleus is obstructed...
Agranulocytes
4. Lymphocytes
A. Abundance: 20-25% of all blood cells in circulation, but only 5% of all lymphocytes are in circulation. The rest are chillin
in lymphoid tissues looking for “bad guys”...
B. Function: Key players in acquired immunity
C. Identifying features: “moon-y” looking nucleus and no granules...
D. Other facts: Main types include B lymphocytes, T lymphocytes, and natural killer cells
5. Monocytes (in circulation) give rise to Macrophages (in tissues)
A. Abundance: 3-8% in blood, where they live for only 8 hrs b/4 entering tissues
B. Function: In tissues, are scavengers (microglia in brain!)
C. Idenifying features: GIANT cell that has a horseshoe-shaped nucleus
D. Other facts: They can ingest up to 100 bacteria in lifetime.
6. Dendritic cells
A. This obscure cell type seems to be related to lymphocytes...
B. It is an antigen presenting cell
C. Called Langerhans cells in the skin…
D. Capture antigens, then migrate to secondary lymphoid tissue and present the antigens to lymphocytes for binding.
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Lab 19: Histology of the Circulatory System
Reading: E Ch. 5 and 8
Part 1: Blood
To distinguish the blood cell types you’ll need to use the 100x (oil immersion) objective. Remember to thoroughly clean the objective
at the end of your session today.
1. Human Blood (HC 1-4 and HC 1-40)
A. red blood cells (erythrocytes)
B. white blood cells (leukocytes)
i. neutrophils
ii. eosinophils (fairly rare)
iii. basophils (very rare)
iv. lymphocytes
v. monocytes
C. platelets
Part 2: Blood Vessels
1. Artery, Vein, Nerve (HG 2-121)
A. artery
i. tunica interna (intima)
a. endothelium
b. internal elastic membrane
ii. tunica media
iii. tunica externa (adventitia)
B. vein
i. tunica interna (intima)
a. endothelium
ii. tunica media
iii. tunica externa (adventitia)
C. nerve
2. Look for a capillary in the loose connective tissue surrounding the artery and vein. Note the thinness of its walls.
Summary Question
1.
2.
3.
4.
5.
6.
7.
Which blood cells carry oxygen?
Which are phagocytic?
Which respond to sites of inflammation?
Which are abundant in allergic reactions?
Why is the wall of an artery typically thicker than that of a vein?
Why is the diameter of an artery typically smaller than that of a vein?
What type of epithelium lines capillaries? What is the name of this lining?
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External Brain 19: Circulatory Histology
91. Describe the function and composition of blood.
92. List the five types of leukocytes in order of their relative prevalence in normal blood and classify each
type as a granulocyte or agranulocyte.
Your Task
1. Consider conditions in which different white blood cells will be abnormally abundant.
2. Why are there so many anatomical differences between arteries, veins, and capillaries? (Link structure to function).
Bio 6: Human Anatomy
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Fall 2013: Riggs