Transcript Blood Vessels

Mammalian Circulatory System
Circulatory Systems
• There are both open and closed systems.
– Insects have an open circulatory system (blood
leaves the heart and flows freely throughout the
body)
– Mammals have a closed system (blood is at all
times contained within a series of vessels)
• In the 17th century William Harvey established
that we have a cyclic system (blood flows in
one direction)
Circulatory Cycles
• There are 3 primary circulatory cycles:
– Cardiac Cycle – the route of blood within the
heart
– Pulmonary Cycle – the route of blood between
the heart and lungs
– Systemic Cycle – the route of blood between the
heart and the body
Three key aspects of a closed system
• Vessels – to transport blood
• A pump (heart)- to move blood throughout
the body
• A transport medium – a specialized fluid
tissue to carry vital elements
Why do we need a transportation system?
• What does our transportation system have to
do with maintaining homeostasis?
Blood Vessels
• Many of the names of
vessels comes from the
Latin or Greek names.
• Remember interest in
the body has been since
the dawn of time!!!
How blood is transported
• Arteries:
– Carry blood away from the heart
– Rigid/Elastic to take blood under
high pressure (from heart)
• Capillaries:
– Very thin narrow where diffusion of
gases and materials occurs
– opens and closes to regulate blood
flow (e.g. stress, eating, etc...)
• Veins:
– Loosen to expand more (controlled
by smooth muscles)
– Store great quantities of blood
Keeping Blood Moving
• Veins posses one-way valves that keep blood moving
in one direction.
• Muscle contractions squeeze the veins to force blood
that can be under negative pressure to move
towards the heart.
• Varicose Veins –
prolonged periods of
standing without leg
contractions can
increase the risk of
developing faulty
valves
Another Look at Blood Vessels
Important ones to note
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Aorta – main artery from heart.
Mesenteric – digestive system
Renal – Kidney
Iliac – Hip/Pelvic
Hepatic – Liver
Inferior Vena Cava – blood to heart from lower
Superior Vena Cava – blood to heart from upper
Carotid Artery – neck vessel to brain.
Jugular vein – neck vessel from brain
Pulmonary – Lung
Cardiac - Heart
The Heart
The Heart
• Located within the
thoracic cavity
positioned more on the
left side of the body
• The heart is protected
by fat and a
pericardium. (a bilayer
tissue filled with fluid)
How Blood Circulates: The Heart
The Heart
• Contraction of ventricles
– Larger of heart chambers
– Takes blood in from the atria
– Pumps blood out to the
lungs/body
• Contraction of atria
– Smaller chambers
– Takes blood in from
lungs/body
– Pumps blood into the
ventricles
• Coordinated beating of
atria then ventricles
Cardiac Cycle
• Right Atria receives de-oxygenated blood
Returned from the body. Pumps it to:
• Right ventricle - receives blood from R. atria
and pumps it out to the lungs for oxygen.
• Tricuspid valve prevents back flow from
ventricle to atria. (Atrioventricular valve)
Cardiac Cycle cont.
• Left Atria receives oxygenated blood from the Lungs
and pumps it to:
• Left ventricle which then pumps it out to the body
(Leaving the heart).
• Bicuspid valve prevents back flow from ventricle to
atria.
• Semi-lunar valves prevent backflow between both
ventricles and their arteries
Coordination of the Beating
• The Heart cells naturally
beat without conscious
control.
• Specialized cells in the right
atria called the SA Node
(pacemaker) send an electric
impulse to neighboring cells
stimulating them to
contract.
• The atria beat top-down.
• The ventricles beat bottomup
• Cardiac Cycle
• Without coordination of the electric signal, the heart
cells would all beat randomly (fibrillation)
- These nerve impulses are detectable using an
electrocardiogram (ECG) See Fig 9.19 pg 317
- Drug overdoses, electric shock, or other damage
can trigger random fibrillations. This would need ro
be corrected by providing a strong electrical current
directly to the heart. AKA De-fibrillation.
Heart Regulators, Fitness and
Disease
Regulation
• At rest the S-A node fires about 70 beats/min.
• During activity, stress or fear, CO2 builds up in the
body becoming carbonic acid.
• Sensory receptors transmit this to the medulla
oblongata (brain) and stimulate the release of
noradrenaline
• Noradrenaline is a stimulant that causes the heart
to beat faster.
Cool Down
• Once the stress is gone the heart is still
pumping.  heart rate =  blood pressure.
• This pressure on the arteries triggers sensory
receptors within the artery wall to send a
signal to the medulla to release acetylcholine.
• Acetylcholine slows heart rate back to normal
levels
Cardiac Output and Fitness
• Cardiac Output is the amount of blood pumped
by the heart in a time given time period. It provides
a measure of blood pumped & amount of oxygen
delivered to body.
• CO = stroke volume x heart rate
Stroke volume - amount of blood pumped out of
the heart per beat.
• AVG (S.V. = 70 ml) x ( H.R. = 70 b/m) = 4900 ml/min.
***~5 L in body***
Ailments and Diseases
• Poor fitness decreases
the distensibility
(stretchiness) of the
ventricles. ( Stoke vol.)
• Septum defect - heart
chamber between the
ventricles fails to close
at birth causing “Bluebabies”. (low oxygen)
• Heart Murmur - one or more heart valves
does not open/close restricting the smooth
flow of blood in the heart.
Tricuspid valve
with a faulty valve
door.
The Lymphatic System
The Other Transport System
• The Lymphatic system is the network of glands
and vessels throughout the body that
transports a near colourless fluid called
Lymph.
• This vascular system (not found in all animals)
helps in immunity and maintaining osmotic
balance.
• It is transported throughout the body using
muscle contractions and one-way valves, like
blood in veins.
Works with Cardiovascular System
• Some plasma that
escapes the capillaries to
bath the body cells does
not re-enter the
capillaries. This fluid is
absorbed into the
lymphatic system and
returned to the
cardiovascular system
through ducts near the
heart.
Immunity support
• The Lymphatic system also aids in transporting
white blood cells that guard the body against
infection.
• Lymphocytes (White Blood Cells) originate in
the lymph nodes of the body. (Think swollen
lumps in your throat when you are sick)
Blood Pressure
• Blood Pressure is described using two parts:
– Systolic Pressure- is the highest pressure reached
during a ventricular contraction.
– Diastolic Pressure- is the lowest pressure reached
just before the next ventricular contraction.
– Blood Pressure is recorded in mmHg (mm
Mercury). Normal range equals 120/80 mmHg.
Hypertension
• Hypertension is a chronically elevated high blood
pressure. It can be associated with a number of
health problems.
• Any condition that increases the volume of blood or
the rate of blood flow can lead to hypertension
– Ex. High salt intake, high cholesterol, diet, age, fitness.
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http://health.howstuffworks.com/adam-200079.htm
http://www.healthcentral.com/high-blood-pressure/introduction-47-115.html
Arteriosclerosis &Atherosclerosis
Clots, Stroke, and Heart Attacks
Angioplasty
• A procedure used to
open the artery lumen
by compressing or
removing a plaque
deposit.
Coronary Bypass
• Coronary blockages can
lead to major heart
problems. The muscles
of the heart need a
constant supply of
oxygen. During a
bypass vessels are
removed from another
part of the body and
are used to bypass the
blockage.
• READ Pages 322328
• Do #1, 2, 3 & 4
Blood
Transport Medium
Function of Blood
Composition of Blood
Blood Types
Function of Blood
• Transport of:
Oxygen
Carbon Dioxide
Nutrients
Wastes
• Immunity
Composition Of Blood
Blood is a collection of cells
specialized to perform a
particular task. Therefore it’s
considered a tissue.
• 55 % Plasma
- 45% Cells and Cell Parts
Plasma
• composed of:
– clear golden fluid and water
– dissolved substances
– proteins (Fibrinogen & Globulin's)
• Has several functions:
– Transports small molecules and ions
– contains Fibrinogen involved in blood
clotting
– contains antibodies (globulin's) that are
involved in disease fighting
Blood Cells and Cell
Parts
3 Cellular components to blood
• Red Blood Cells
• White Blood Cells
• Blood Platelets
• Plasma:
–Glucose, hormones,
etc. suspended in a
viscous goo
• White Blood
Cells:(leukocytes)
–Protect the cells from
infection/invasion
• Platelets:
–Clot the blood to prevent it from
spilling out when a rupture of the
fluid conduit occurs
• Red Blood Cells:(erythrocytes)
–Transport O2
–99% of all blood cells
Red Blood Cells
• Also called Erythrocytes ~ 5 million/ml
• Main function is to carry Oxygen
• Structure:
– Mature cells have no nucleus and are disk
shaped (to  surface area &  size)
– Cytoplasm contains a molecule called
Hemoglobin
• a iron containing molecule to carry oxygen
• every R.B.C contains > 200 mil. hemoglobin
molecules
White Blood Cells
• also called Leucocytes
• Function: protect the body from infection
There are Two main types of W.B.C. s
• macrophages
–move out of the capillary and digest foreign
materials by phagocytosis
• Lymphocytes
–specialized antibodies that fight infection
Platelets
Cell fragments
• 250 million per cubic centimeter
• Function: Trigger the Blood Clotting
Process
•
Blood Clotting
• Broken or damaged blood vessels release
platelets.
• Ruptured Platelets release chemicals that react
with plasma proteins to make thromboplastin.
• Thromboplastin reacts with prothrombrin to
produce thrombrin (needs calcium)
• Thrombrin causes fibrinogen molecules to join
together to form strands called Fibrin
• Many strands of Fibrin form a mesh or clot that
stops the bleeding
Blood Clot
Blood Clotting
Review of Blood Components
Blood
Plasma
Blood Cells and Blood Parts
White Blood Cells(W.B.C)
-Leucocytes
Macrophages
Lymphocytes
Platelets
Red Blood Cells (R.B.C)
-Erththrocytes
Blood Problems
• Anemia - occurs when there is a shortage of
hemoglobin ib blood
• Leukemia - Cancer of the white blood cells
• A.I.D.S - the H.I.V. virus attacks and destroys
an important type of WBC
• Sickle Cell Disease - abnormal hemoglobin
causes RBC s to have irregular shape
The END