Transcript PP 3 Circulation contd

Circulation Continued
Hepatic vein
Hepatic Artery
Hepatic Portal
Vein
Renal Vein
Mesenteric artery
Structure/
Function
Arteries
Capillaries
Veins
• thick strong walls so it
• 1 cell think so that it
can take blood /
nutrients as close to the
cells that need it and
pick up waste from cells
that the blood can take.
• Oxygen diffuses from
the Red Blood Cells into
the tissue
• Deliver blood back to
the heart
• have valves to stop the
blood from flowing
backwards
• Thin walls / less elastic
tissue / large lumen
compared to arteries
• muscle movement
helps move blood along
can withstand high
pressure blood moves at
•Stretchable walls
•‘spring’ action to
contract
• takes blood to the
body from heart
More on structure
Thick / Elastic fibers /
small lumen (space
where blood flows
through
Arteries
Capillaries
Veins
Similarities
-All carry blood/ plasma/ blood vessels/ have lumen
- Arteries >veins>capillaries (stretchable / elastic)
-(Arteries & capillaries carry oxy blood) / (Veins and capillaries
carry deoxy blood)
-Arteries & veins – connected to heart directly
- Arteries / Veins – have elastic fibers (similar tissues)
- Arteries / Veins – contract & expand (arteries>veins)
Differences
-Veins>Arteries>capillaries (size of lumen)
-Carry blood: Arteries (high pressure) Veins (low pressure)
- No elastic fibers for capillaries
-No valves for arteries and capillaries / valves in veins
-Size : Arteries > Veins > Capillaries
-Veins have thin walls Arteries have Thicker Walls (No walls for
capillaries – only 1 cell thick)
 Blood – material transfer:
- Glucose
- Amino acids
- Inorganic ions
- Vitamins
- Water
- O2/CO2 – diffuse into/ out of RBC
 Arterioles brings blood into capillaries
 Arterioles divide into smaller capillary networks
 Fluid (containing nutrients) leak out of capillaries
especially at the beginning of the capillary bed
 The fluid leaked out of capillaries and now
surrounding the tissue cells is now called tissue fluid
 Waste products like CO2 in the tissue fluid is now
leaks back into the capillaries at the end of the
capillary bed
 The venule carries the blood back to the vein
Blood capillaries have tiny
holes between the cells in
their walls
Blood Plasma (fluid that
leaks out of capillary with
nutrients) passes between
these holes
Lymphocyte (Ly) and platelet (P) located in the lumen of blood capillary.
 RBC – hemoglobin and oxygen transport
 WBC – Phagocytosis / Antibody formation
 Platelets – causes clotting of blood. They are tiny
fragments . Role – to help blood to clot when
vessels are damaged / stop pathogens
 Blood : Several different kinds of cells that float in liquid called
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PLASMA
Red Blood Cells (RBC)
Majority of cells are RBC
Smallest cells
Round with dent (biconcave disks with
no nucleus)
To transport O2/CO2
Red protein = hemoglobin (blue red)
In lungs – when it picks op O2 – oxy-hemoglobin (bright red)
In capillary in tissue bed – O2 is released by the oxy-hemoglobin
and becomes Hemoglobin again
 -Large and always have nucleus
 Part of the body’s defense system against harmful
bacteria . Viruses and other harmful organisms.
 Disease causing organisms = pathogens
 WBC destroy pathogens
Neutrophils : the most plentiful leukocytes in the
bloodstream ; break down bacterial cells in the body
with enzymes stored in the grains in the neutrophils'
cytoplasm
Eosinophils : numbers of these cells in the blood
increase in the presence of allergens (substances which
cause allergies) or parasites
Basophils are the least plentiful leukocytes in the
bloodstreamin beginning the process of inflammation,
one of the body's ways of responding to injury or
irritation that's characterized by redness, warmth,
swelling, and pain in one specific place.
Monocytes : mononuclear leukocytes that
typically have a horseshoe or kidney-shaped
nucleus, and are the largest type of white blood
cell.; help devour microorganisms by phagoytosis
;T hey also devour and digest body cells that have
died or are old, and also help remove other
unneeded cellular material from the body.
Lympocyte: are the second most plentiful type of
leukocyte in the blood, and are smaller than other
types of leukocytes.
 Phagocytes: WBC that kill pathogens by
phagocytosis. Usually first to arrive at the scene and
attempt to destroy the pathogen.
 Phagocytosis – the process by which the phagocytic
WBC puts our finger like projections and enclose a
pathogen into a vacuole (enclosed space) in their
cytoplasm. Then the WBC kills the pathogen.
 1. Phagocytic WBC flows around the bacteria
 2. The WBC traps the bacteria by closing around them
(phagocytosis)
 3. The bacteria is trapped I a vacuole
 4. Enzymes are secreted inside this vacuole by the
WBC to kill and digest the bacteria.
 5. The digested substances are absorbed into the
cytoplasm of the WBC.
 WBC (another kind) known as lymphocytes kill
pathogens by making special proteins known
ANTIBODIES
 These antibodies can kill pathogens directly or make it
easier for phagocytes to kill it.
 There are different antibodies for different pathogens.
 The pathogen (invading organism) has many different
antigens (the different molecules that make up
the pathogen).
 Your WBC lymphocytes recognize your molecules but
not another's
 When a bacteria invades your body for the first time –
(your body has not seen it before) very few antibodies
will be there that can actually recognize the new
antigen.
 It takes a few days for your WBC lymphocytes to make
the right one. That is when you are feeling sick.
 But, if it is a bacteria your body has seen before – the
WBC lymphocytes will not take much time to make
the right antibody.
 You are IMMUNE to the disease when your body can
successfully kill the invading organism by itself.
 Tissue rejection:
- Transplant – taking an organ from one person (the
donor) and giving it to another who needs it (the
recipient)
- (eg. Kidney transplant)
 The cells in the transplant is not the same as the
person who needs it.
 Tissue rejection – occurs when the recipient's immune
system recognizes the donor’s as a foreign object and
attacks it.
 To avoid tissue rejection – doctors try to find a donor
who has similar antigen to the recipient .
 Best to have identical twins for this.
 If not – recipient will have to take
immunosuppressant drugs (drugs to turn down
the immune system).
How blood clotting occurs:
- Damaged blood vessel is rough not smooth (when you
get a cut on your finger)
- Platelets bump into the rough parts and react with
them
- Fribrinogen (a protein) found in blood plasma also
reacts with the platelets at the same time.
 The reaction between the platelets and the fibrinogen
causes the soluble fibrinogen to become an insoluble
protein called Fibrin.
 The Fibrin is long and fibrous (looks like a net) and
captures RBC / WBS / Platelets and forms a blood clot.
 A dried blood clot is called a scab
 Under the scab – the skin heals by forming new skin
cells . It continues to do this until a new layer of skin
has formed – that is when the scab falls off.
 Circulation of body fluids:
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Network of capillaries – capillary bed
Capillaries have tiny holes in their walls
Blood plasma can leak through the holes (in between
all the cells in the tissue and fills that space) Now
called Tissue Fluid
WBC can move through these tiny holes but RBC can
not (can’t change shape like WBC)
Therefore tissue fluid does not contain RBC
 Tissue fluid – continuous pathway between blood
plasma / cells / tissue
 Everything that moves between the blood and tissue
diffuses through tissue fluid
 Tissue fluid carries oxygen and nutrients to the tissue
cells
 Leaks back to capillary bed with waste from cells
including CO2
 Tissue fluid that does not return to the capillary bed
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returns to the blood via lymph vessels
Lymphatic capillaries embedded in tissue collect the
remaining tissue fluid
Once the fluid is inside the lymphatic capillaries it is
now called lymph
The Lymph capillaries have valves like veins that
prevent the back flow of tissue fluid back into the
tissue
Lymph capillaries join to make up the lymph vessels
 These take the fluid (lymph) into large veins called the
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subcalvian veins (just under the collarbone)
The lymph flows into the blood in these veins
The fluid moves due to the lymph vessels that pass
alongside muscles
These squeeze on lymph vessels when the muscles
contract
These lymph vessels pass through the lymph nodes
where WBC are collected
Also passes along fatty acids and glycerol to parts of
body.