Transcript Circulation and Blood

Circulation and Blood
Nelson p. 240-279
Practice Sets
 Importance
of a Circulatory System
Read p. 242-243
Questions p243 #1-4
 Blood Vessels Read p. 250-253
Questions p.253 #1-4
 Mammalian Heart Read p. 256-258
Questions 1-4
Differentiate between OPEN and
CLOSED circulatory systems
Closed System – the blood is always contained
in either the heart or blood vessels. It never
leaves them. Example worms, humans, octopus
 Open System – The blood is contained in a
heart(s) and blood vessels but at some point is
pumped into the body cavity and bathes the
cells. This is when the oxygen/nutrients leave
the blood and the wastes/carbon dioxide enter
the blood.
 Example: snails, lobsters, crabs

3. One advantage and one
disadvantage of an open system
– does not require a lot of
energy to build and repair blood vessels,
create pressure
 Disadvantage – blood cannot be directed
to specific areas
- Limits the size that the organism can grow
to
 Advantage
4.
Sponge
Snail
Earthworm
similarities
differences
All require
the delivery
of nutrients
and
removal of
waste
All cells
bathed with
fluid from
environment
No heart
Open
system
Closed
system
Heart
present
Heart
present
5.
 MCO’s
need a circulatory system to
ensure that nutrients are brought to and
wastes are removed from every cell in the
organism including the cells deep within
the organisms body.
Blood Vessels
How do arteries differ from veins?
Arteries
 Carry blood away
from the heart
 Thick walls made of
muscle and
connective tissue
 Able to stretch




Veins
Carries blood towards
heart
Walls made of smooth
muscle
Blood pressure is
very low(15-20mmHg)
Valves prevent blood
from flowing
backwards
Veins (con’t)
 Muscular contractions
assist forward
movement of blood
 Reservoir for blood
(50% of volume)

What causes a pulse?
 A pulse
occurs when the diameter of the
artery changes as the heart contracts and
relaxes
Define vasodilation and vasoconstriction.

Vasoconstriction
occurs when a nerve
impluse causes
muscle in the
arterioles to contract
and this reduces the
diameter of the blood
vessel and decreases
the flow of blood to
tissues
 (become pale)

Vasodilation occurs
when the muscle in
the arterioles relaxes
and the diameter of
the blood vessel
increases and the
flow of blood to the
tissue increases
 (blushes, release
heat)
What are the functions of capillaries?
The functions of the capillaries are
 site of gas exchange between blood and
cells
Practice Set (cont’d)
 Mammalian
Heart Read p. 256-258
Questions p.258 # 1-4
 Components
of Blood Read p. 244-246
Practice p. 246 #1-8
The Mammalian Heart
What is the function of the AV valves and the semilunar valves?
 Ensure
the one-way flow of blood
throughout the circulatory system
What is angina and what causes it?
 Coronary
circulation includes the blood
vessels which supply the heart muscles
with oxygen and nutrients.
 Angina occurs when a coronary artery is
blocked and not enough oxygen can get to
the heart. It caused chest pains and may
lead to heart attack
What are coronary bypass operations and why are they performed?
 A coronary
bypass operation involves
replacing a coronary artery blocked by fat
and plaque deposits with a vein removed
from another part of the patient’s body
Differentiate between the systemic circulatory system and the
pulmonary circulatory system.
Components of Blood
Why is blood considered to be a tissue
Blood is considered to be a tissue
because it is made of several types
of cells which work together for a
common purpose
2.
Name the two major components of blood.
1. plasma –
2. blood cells -
List three plasma proteins and indicate the function of
each.
Plasma Proteins
1. Albumins – maintain osmotic
pressure (water balance)
2. globulins – help protect against
invading microbes
3. fibrinogens – role in clotting of
blood
4. What is haemoglobin?
Haemoglobin is a molecule
containing an iron pigment molecule
in a protein molecule.
It’s function is to increase the ability
of blood to carry oxygen (X70)
What is anemia?
Anemia is an illnes caused by a lack
of red blood cells.
It’s symptom is extreme fatigue
(tiredness) and is sometimes caused
by too little iron in the diet.
What causes the production of pus?
Pus is produced from the fragments
of used white blood cells
What is the role of platelets?
The role of platelets is to initiate
(start) the blood-clotting reponse to
and injury.