Transcript Circulatory System Notes

The Transport System
Core 6.2
Circulatory System

Most animals have a circulatory system
including a pumping device – heart
– Open Circulatory System:
 System may have
 Organs are bathed in blood

 Ex.
– Closed Circulatory System
 Blood stays
 Ex.
6.2.5 Explain the relationship between the structure and
function of arteries, capillaries and veins.
 Circulation
in Vertebrates involves a
closed system that consists of:
1. Arteries
 Function:
- branch into smaller vessels called
 Structure:
– Have a
– Very
– Inner diameter is small
6.2.5 Explain the relationship between the structure and
function of arteries, capillaries and veins.
2. Capillaries:
 Function:
 Structure:
– Walls are
–
in diameter – RBC’s pass
through single file
–
to increase total crosssectional area
– Results in low pressure and slower flow (
–
penetration into all tissues
for exchange and
)
6.2.5 Explain the relationship between the structure and
function of arteries, capillaries and veins.
 Mechanisms for Exchange between
Blood and Tissue:
–
–Materials are
in cell membrane of capillary
endothelial cell (endocytosis) travel
across cell and
–Water and dissolved molecules (not
proteins) filter through clefts between
adjacent endothelial cells
6.2.5 Explain the relationship between the structure and
function of arteries, capillaries and veins.
3. Veins
 Function:
; small veins called
lead away from capillaries
and branch into the larger veins
 Structure:
–
;
– Smooth muscle layer is
inner diameter is
and
6.2.5 Explain the relationship between the structure and
function of arteries, capillaries and veins.
– Veins have
to assist in moving
blood up to the heart (against gravity) and also
depend on squeezing from muscles
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
William Harvey (1628)
– English physician that was the first to
accurately describe how blood is pumped by
heart
– published work marked the
(understanding bodily processes in terms of
chemistry and physics)
6.2.1 Draw and label a diagram of the heart showing the four
chambers, associated blood vessels, valves and the route of blood
through the heart.
6.2.2 State that the coronary arteries supply heart muscle with oxygen and
nutrients.
6.2.3 Explain the action of the heart in terms of collecting blood, pumping
blood, and opening and closing of valves.

Circulation Pathway in
Humans
Valves
– 4 chambered heart 
– 2 separate pumps separated
by the
– One-way valves separate
chambers and 
– Muscles squeeze the chamber
in a powerful 
Septum
1.
& 1b. Deoxygenated blood returns to heart through
2.
through
3.
through
to
to
4.
5. To the
– gas exchange takes place and blood is oxygenated
6.
9.
7.
Through
to
8.
through
to
– very large artery carries oxygenated blood to the body

Circulation outside of the
heart is divided into:
– Pulmonary circulation:
Circulation = movement of blood
– Systemic circulation:
 The heart itself is supplied with
oxygen and nutrients by the
.
Pulmonary circulation
Right
Systemic circulation
Left

Circulation in other
vertebrates
–
are characteristic of birds
and mammals

 no
mixing of oxygenated and
deoxygenated blood
– Fish have a
 Systemic circulation
under very low pressure,
blood moves sluggishly
– Amphibians and reptiles
have
–2
atria and 1 ventricle
 Oxygenated and
deoxygenated blood

show
beginning of development
of septum (reduces
mixing)
6.2.4 Outline the control of the heartbeat in terms of myogenic
muscle contraction, the role of the pacemaker, nerves, the
medulla of the brain and epinephrine (adrenaline).

Contraction of the heart
– Cardiac cells tend to
 Contraction of one heart cell stimulates
– Contraction of atria is initiated by
 wave of contraction passes through atria to
 impulse transmitted to
and wave continues
6.2.4 Outline the control of the heartbeat in terms of myogenic
muscle contraction, the role of the pacemaker, nerves, the
medulla of the brain and epinephrine (adrenaline).
 When the network in the atria contracts,
blood in the atria flows into the ventricles.
 When the ventricles contract, blood flows
out of the heart.
– Heartbeat is initiated by the
 Pacemaker is located in the
 The impulse spreads from the pacemaker to a network
of fibers in the atria.
Sinoatrial (SA)
node
– The impulse is picked up by a bundle of fibers called
the
and carried to
the network of fibers in the ventricles.
 AV node is located on septum between atria

– fibers that
extend from AV node
into walls of
ventricles

further branch into all
parts of ventricular
muscle
Bundle
of His
Atrioventricular
(AV) node
Purkinje
fibers

Cardiac muscle cells are electrically coupled by
– Intercalated disks consist of desmosomes and gap
junctions
– Desmosomes are made of intercellular cement and
protein
– Gap junctions allow ions to pass through to stimulate
the neighboring cell

How is the pacemaker
regulated?
– Nervous control of heart
is a
– Heart receives impulses
from a control center in
the
,
via 2 nerves
 One nerve
, the
other
(antagonistic –
opposite)
–
(Adrenaline), which is
produced by the adrenal
glands, travels through
the bloodstream and
Which response is caused by the release of epinephrine?
Why would the heart rate need to increase?

Cardiac Cycle
– Heart chambers alternate between
– Contraction phase is called
, and
relaxation phase is called
– Heart sounds heard with a stethoscope are caused by
– Sound pattern is “lub-dup, lub-dup, lub-dup”
– First heart sound (“lub”) is created by closing of AV
valves
– Second sound (“dup”) created by closing of semilunar
valves
– Heart murmers – occur when
– Electrocardiograms –
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
Blood Pressure and Rate of Flow
– During systole, heart
– During diastole, heart
–
is measured to record
the regular cycle of pressure in the arteries as
the heart contracts
 Usually measured in
with a
 Average pressure for young adult male is
– Blood pressure varies by location in
body and
 Resulting gradient of pressure causes
fluids move from regions of
–
 Differences in systolic and diastolic
pressures diminish with
 By the time blood reaches capillaries the
flow is
(rather than surging
as in the arteries)
 Pressure continually drops through
arterioles and capillaries and is the
lowest in the veins closest to the
heart
 Rate of flow
–Highest in
–Lowest in in
–Increases again in
Why does rate of flow in the capillaries
need to be low?
6.2.6 State that blood is composed of plasma, erythrocytes,
leucocytes (phagocytes and lymphocytes) and platelets.
6.2.7 State that the following are transported by blood: nutrients,
oxygen, carbon dioxide, hormones, antibodies, urea and heat.

Composition of blood
1. Plasma :
 liquid matrix constituting
 Plasma is
with a variety of dissolved
substances:
–
organic anions (Cl-, HCO3-)
(Na+, Ca+2, K+, Mg+2) and
–
(fibrinogen, albumins, and
globulins – important for osmotic pressure in plasma,
help to transport substances, blood clotting)
–
(glucose, fats,
phospholipids, amino acids, lactic acid, cholesterol)
–
– urea, ammonia and uric
acid
–
– regulatory chemicals
– 3 gases found in small amounts –
–
–
distribution to all tissues
2. White Blood Cells  Five major types:
 Fight infections
 Monocytes and neutrophils are
 Eosinophils
 Basophils release
– causes
(increased blood flow to
injured site) – part of inflammatory response
 Lymphocytes –
–
part of specific immune response resulting
from exposure to an
(foreign substance in body)
–
(globulin
proteins) to destroy antigen – specifically fight
antigen that stimulates production
3. Red Blood Cells –

 Approximately
 Live approximately
destroyed by liver and spleen
 Formed in
bones, skull, ribs, and pelvis)
 Filled with
gives red color)
*Some animals (mollusks
and arthropods) have
–
contains Cu instead of Fe
– dissolved in plasma not
in cells
–
(in long
(carries oxygen,
4. Platelets – play a part in the

Whole blood –

Blood plasma –

Blood serum –

Blood clotting
–
converts to
comes out of solution and
(forms a hard lump or clot)