Circulatory System Flashcards

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0
Q

Blood Basics

How much, what is it, what’s it made of

A
  • there are about 4.5 litres of blood in your body
  • blood is a connective tissue
  • made up of 2 major components: plasma & cells
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1
Q

Functions of blood

A
  1. Carry O2 and nutrients to cells
  2. Carry secretions and waste away from cells
  3. Has phagocytic cells to fight infections
  4. Helps establish pH
  5. Equalizes body temperature
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2
Q

Plasma

A
  • fluid portion of blood (55%)

- contains water, proteins, nutrients, salts, gases (CO2 and O2), wastes (urea), hormones, etc

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3
Q

Role of plasma proteins

A
  • increases osmotic pressure inside capillaries (blood is hypertonic to tissue)
  • fluid leaving the capillaries is replaced by water flowing in to balance the concentration gradient
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4
Q

Red Blood Cells

name, shape, where formed, function, where destroyed

A
  • “erythrocytes”
  • red biconcave disks that transport O2
  • formed in bone marrow by stem cells
  • mature RBC’s have no nuclei
  • live about 120 days
  • contain hemoglobin which carries the O2
  • old RBC’s destroyed by liver & spleen, where iron is recycled & the rest of the cell is used to make bile
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5
Q

White Blood Cells

Name, functions, where made

A
  • “leukocytes”
  • wbc’s remove dead or worn out body cells
  • live about 300 days
  • protect against infection (bacteria or virus)
  • made in bone marrow from stem cells & in the spleen, lymph nodes, & tonsils (lymphatic system)
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6
Q

5 types of WBC’s

A
  • lymphocytes: b & T cells involved in immune response
  • monocytes & neutrophils: search & destroy invaders (phagocytes)
  • eosinophils: fight allergic reaction
  • basophils: part of inflammatory response (release histamines)
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7
Q

Divisions of leukocytes

A
  • agranular
    • lymphocytes
    • monocytes
  • granular
    • basophils
    • neutrophils
    • eosinophils
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8
Q

Platelets

What, where made, function

A
  • fragments of cells
  • made in bone marrow from stem cells
  • have no nuclei
  • last 5-9 days
  • involved in blood clotting
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9
Q

Blood clotting process

A
  • thromboplastin released when platelets/tissue is broken open
  • converts plasma protein prothrombin into thrombin (with help of CA+)
  • thrombin coverts fibrinogen into fibrin
  • fibrin causes clotting because it’s an insoluable protein
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10
Q

What do blood banks do to prevent blood clotting?

A

Remove CA+ from donor’s blood

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11
Q

What is the name of the portion of blood that is not plasma?

A

Formed elements (cells & platelets)

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12
Q

What is the role of plasma?

A

To dissolve blood clots

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13
Q

Function of gas trade

A
  • delivers nutrients/O2 to tissue cells & remove wastes/CO2
  • O2 picked up in lungs, dropped off in tissues
  • CO2 picked up in tissues, dropped off in lungs
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14
Q

O2 bonding sites

A
  • O2 bonds to hemoglobin (HB) in RBCs
  • 4 O2/HB bonding sites
  • HB + O2 -> HbO2 (oxyhemoglobin)
  • blood at capillaries has enough pressure to force h2o into tissue spaces
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15
Q

How is CO2 carried in plasma?

A
  • as bicarbonate ion (HCO3)
  • CO2 + H2O -> carbonic acid (H2CO3) -> H+ (absorbed by buffer HB) + HCO3 (diffuses in plasma)
  • some CO2 is transported as carbaminohemoglobin (HbCO2)
16
Q

Interstitial fluid

A

Surrounds cells

17
Q

Capillary bed

A
  • network of capillaries where materials are exchanged between blood & cells
  • every cell is within 2-3 cell diameters from a capillary for better diffusion
18
Q

What happens at arterial end of capillary?

A

H20, glucose, amino acids, and O2 are forced out of the capillary because the hydrostatic blood pressure in capillary (40mm/hg) is higher than the osmotic pressure in tissues (21mm/hg)

19
Q

What happens at center of capillary?

A

Hydrostatic pressure = osmotic pressure, so nutrients & waste diffuse on their own concentration gradient without needing pressure

20
Q

What happens at venous end of capillary?

A

Osmotic pressure (21mm/hg) is higher than the hydrostatic pressure (15mm/hg) and this force pushes h20, co2, and waste molecules into capillary

21
Q

Capillary-tissue fluid exchange

A

The nutrients and wastes are exchanged by moving from high to low concentration (with concentration gradient) due to osmosis and diffusion

22
Q

Removal of tissue fluid

Why, how

A
  • prevents buildup of interstitial fluid (lymphatic system helps)
  • tissue fluid enters lymph vessels and eventually ends up rejoining the blood
23
Q

How is homeostasis maintained during injury?

A
  • blood pressure drops, so less tissue forms at the arterial end and more tissue is absorbed into blood at venous end of capillary network
  • net flow of tissue fluid into capillary network -> rise of blood volume -> blood pressure returns to normal
24
Q

Types of blood vessels in cardiovascular system

A
  • arteries (and arterioles)
  • capillaries
  • veins (and venules)
25
Q

Arteries

A
  • carry oxygenated blood away from heart and to capillaries
26
Q

Capillaries

A
  • permit exchange of material within the tissues
27
Q

Veins

A
  • return deoxygenated blood from capillaries to hear
28
Q

Layers of the artery

A
  • inner layer: composed of endothelium with basement membrane containing connective fibers
  • middle layer: thickest layer, consists of smooth muscle that contracts to regulate blood flow & pressure
  • outer layer: fibrous connective tissue near middle -> becomes loose connective tissue at periphery
29
Q

Arterioles

A
  • small arteries
  • middle layer is mostly smooth muscle, which can be contracted or dilated to regulate blood pressure (the more vessels dilated, the lower the blood pressure)
30
Q

Layers of capillary

A

Single layer of epithelium with a basement membrane

31
Q

Layers of veins & venules

A
  • same 3 layers as arteries, but have less smooth muscle and connective tissue -> veins are thinner than arteries
  • since veins are thinner, they can expand more (veins have about 70% of blood)
32
Q

Valves

A
  • in veins (especially veins in lower extremities that must carry blood against gravity)
  • allow blood to flow only towards the heart when open
  • prevent backwards flow of blood when closed