Transcript File

Settler
Explain why large, active animals need a
transport system. (3 marks)
Exam answer
Single Circulation – e.g. fish
Blood passes through heart
ONCE per complete circuit
Blood pressure reduced as blood passes through the gill
capillaries - slows down flow to the rest of the body
Limits the rate of delivery of O2 and nutrients to cells and
removal of waste
Efficient for the level of activity of fish but not mammals –
also fish do not maintain their body temperature – need to
respire relatively less compared to mammals
Double Circulation – more efficient - e.g. mammals
Heart is composed of two separate pumps – right side pumps
blood to the lungs to pick up oxygen; the blood is returned to
the left side; the left side pumps oxygenated blood rapidly and
at high pressure to the body; the blood is returned to the right
side
Higher level of activity (energy) and need to maintain their
body temperature at 370C – through respiration
Need to deliver and remove materials to and from cells rapidly
– achieved by delivering blood at high pressure to tissues.
Pulmonary – oxygenates blood & removes CO2
Systemic – oxygenated blood from lungs pumped
rapidly at an increased pressure by the heart
Blood passes through heart
TWICE per complete circuit
1 Size
1)If an animal has several layers of cells, any oxygen
and nutrients will not reach the deeper cells within
the body
•Explain why large, active animals need a
transport system
(Grade C –B)
2 Surface Area to Volume Ratio
• Larger animals have a small surface-areavolume-ratio.
• Larger volume due to range of tissues.
• Their surface area is not large enough to
supply all the oxygen and nutrients needed by
internal cells.
3 Level of Activity
• If an animal is active it will require a good
supply of oxygen and nutrients to supply the
energy for movement.
• Mammals also require more energy to keep
themselves warm.
From the spec.....
• explain the need for transport systems in
multicellular animals in terms of size, level of
activity and surface area:volume ratio;
What is the difference between these two circulatory systems?
What are the advantages of a double circulation?
Module 2
Exchange and transport
1.2.6 Structure of the mammalian
heart
Closed circulatory systems
Advantages of Double over Single
• Double circulatory system – blood travels
through the heart twice for each complete
circuit of the body
• Efficient so deliver nutrients quickly
• Can increase pressure of blood flow
• Quicker supply oxygen
• Can keep pressure to exchange surface low to
avoid damage
Starter
• Label the diagram of the heart – previous
knowledge from KS4
•Label the structures of the heart
(Grade E - D)
Learning Objectives
Success Criteria
• Label the structures of the heart
(Grade E - D)
•
To understand the
structure of the mammalian • Describe with the aid of
diagrams/photographs, the
heart
external and internal structure of
the mammalian heart
(Grade C –B)
• Explain the difference in the
thickness of the walls of the
different chambers of the heart
in terms of their functions
(Grade B – A)
RIGHT
LEFT
Pulmonary artery
(a)
(c)
Semi-lunar valve
Deoxygenated blood
from the body
(d)
Vena cava (main vein)
Right atrium(f)
(b)
Aorta
(main artery)
Oxygenated blood
from the body
(e)
Pulmonary vein
(g)Left atrium
Tricuspid valve
(i)Bicuspid valve
Tendons
(j)
(k)Left ventricle
(h)
Papillary muscle(l)
(m)
Right ventricle
•Label the structures of the heart
(Grade E - D)
The human heart
The heart is a muscular
organ located between the
lungs in the centre of the
chest (thorax), and is about
the size of a fist.
It pumps blood continuously
around the body. An organism
can lose conscious within just
a few seconds if the brain is
deprived of blood.
In foetuses, the heart begins
beating about 5–6 weeks after
conception.
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© Boardworks Ltd 2008
Cardiac muscle
The heart mainly consists of cardiac muscle tissue, which
like smooth muscle (but not skeletal muscle), contracts
involuntarily.
Cardiac muscle is
made up of cells that
are connected by
cytoplasmic bridges.
This enables electrical
impulses to pass
through the tissue.
It contains large numbers of mitochondria and
myoglobin molecules.
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© Boardworks Ltd 2008
Structure of the heart
•Explain the difference in the thickness of
the walls of the different chambers of the
heart in terms of their functions
(Grade B – A)
•Explain the difference in the thickness of the walls of
the different chambers of the heart in terms of their
functions
(Grade B – A)
Task
• Heart dissection – identify all the internal
parts of the heart and external parts of the
heart.
• Label each part with its function
Include – tendinous cords, septum,
•Describe with the aid of
diagrams/photographs, the external and
internal structure of the mammalian heart
(Grade C –B)
Can you identify the following
without looking at your diagram?
1. The vessel which carries blood to the
lungs. Pulmonary artery
2. The valve between the left atrium and
ventricle.
Bicuspid
3. The chamber which receives deoxygenated
blood from the body.
Right atrium
4. The vessel which carries blood pumped out
of the left side of the heart.
Aorta
5. The vessel which carries blood into the
heart from the lungs. Pulmonary vein
Plenary
• Heart drag and drop
• Homework – worksheet on heart
From the spec...
(b) explain the meaning of the terms single circulatory system and double
circulatory system, with reference to the circulatory systems of fish and
mammals;
(c) explain the meaning of the terms open circulatory system and closed
circulatory system, with reference to the circulatory systems of insects and fish;
(d) describe, with the aid of diagrams and photographs, the external and internal
structure of the mammalian heart;
(e) explain, with the aid of diagrams, the differences in the thickness of the walls
of the different chambers of the heart in terms of their functions;