WELCOME BACK!!
• CONGRATULATIONS ON PASSING THE EXAM!• BUT NOW KEEP UP THE GOOD WORK…IT’S
GOING TO BE A BUSY TERM!• NEW LEARNER GUIDE – READ AND MAKE USE
OF IT!• MAKE NOTE OF IMPORTANT DATES!
– PRAC 1 – NEXT TUESDAY, 24TH!– CLASS TEST 1 – NEXT WEDNESDAY, 25TH!
NATIONAL SCIENCE WEEK
• Organised by the Department of Science & Technology
• Launch hosted by UJ, Soweto Campus, 28th July • Aims to excite youth with science at a young age!• You are invited free of charge!• Launch day: 07:00 – 15:00• Register after class with ID number• The rest of the week 14:30 – 15:30
POSTER PROJECT
• GROUPS OF 5 – names on back of poster• A3 POSTER• ANY BIOLOGICAL TOPIC• INTERESTING, INFORMATIVE, PICTURES,
DIAGRAMS, COLOURFUL, FUN• TARGET: High School Students• DUE DATE: Next Tuesday, 24th July in class!!
TRANSPORT SYSTEMS IN
ANIMALS
(Campbell and Reece (2010), Chapter 42: P.898-915)
CIRCULATORY SYSTEMS IN ANIMALS Many invertebrates do not have
a circulatory system at all. Their cells are close enough to
their environment for oxygen, other gases, nutrients, and waste products to simply diffuse out of and into their cells.
E.g. Hydra
CIRCULATORY SYSTEMS IN ANIMALS• In animals with multiple layers of cells,
their cells are too far from the external environment for simple osmosis and diffusion.
• In higher animals, there are two primary types of circulatory systems -- open and closed.
CIRCULATORY SYSTEMS IN ANIMALSOPEN- CLOSED-
CIRCULATORY SYSTEMS IN ANIMALSOPEN- • The circulatory fluid – Hemolymph (is the
same as interstitial tissue fluid)• The heart pumps hemolymph through
vessels into sinuses (open fluid-filled spaces)
• Certain substances are exchanged between the hemolymph and the cells.
• Hemolymph returns to the heart through pores.
• The heart is a tubular structure.
CIRCULATORY SYSTEMS IN ANIMALSCLOSED- • Circulate blood entirely within
vessels.• So the blood is distinct from the
interstitial fluid.• Chemical exchange occurs between
the blood and interstitial fluid as well as between interstitial fluid and body cells.
DOUBLE CIRCULATION
• The circulatory systems with two distinct circuits.
• The pumps of the two circuits serve different tissues but are combined into a single organ, the heart.
• The two circuits are called:1. Pulmonary circuit 2. Systemic circuit
DOUBLE CIRCULATION
1. Pulmonary circuitThe heart pumps deoxygenated blood to the lungs and oxygenated blood back to the heart.
2. Systemic circuitThe heart pumps oxygenated blood to the body cells and the deoxygenated blood back to the heart.
DIFFERENT BLOOD VESSELS: ARTERIES, VEINS AND CAPILLARIES
FUNCTIONS OF CAPILLARIESCapillaries: Connect arteries and veins – are structurally suited to facilitate the exchange of substances between the blood in the capillaries and the interstitial tissue fluid
FUNCTIONS OF ARTERIESArteries: transport oxygenated blood except for the pulmonary artery. Main artery is called the Aorta – pumping oxygenated blood from heart to rest of body.Other arteries:Renal artery (kidney)Hepatic artery (liver)
FUNCTIONS OF VEINSVeins : transports deoxygenated blood except for the pulmonary vein. Main vein is called the vena cava – pumping deoxygenated blood towards the heart from the rest of the body.Other veins:Renal vein (kidney)Hepatic vein (liver)
THE HUMAN CIRCULATORY SYSTEM: HEART AND ASSOCIATED VESSELS
THE HUMAN CIRCULATORY SYSTEM: HEART AND ASSOCIATED VESSELS
Mammals have a four-chambered heart with two atria and two ventricles
The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood
The mammalian cardiovascular system meets the body’s continuous demand for O2.
Blood begins its flow when deoxygenated blood flow from the body into the right atrium.
Blood then flows from the right atrium into the right ventricle through the tricuspid valve
The blood is then pumped into lungs, through the semilunar valve via the pulmonary artery.
In the lungs, the blood loads O2 and unloads CO2. Oxygen-rich blood from the lungs enters the heart
via the pulmonary vein at the left atrium Blood then flows into the left ventricle through the
bicuspid valve. This blood is then pumped through semilunar
valve into the aorta with takes blood to the entire body.
Deoxygenated blood returns to the heart through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs)
The superior vena cava and inferior vena cava flow into the right atrium.
The atrioventricular (AV) valves (tricuspid and bicuspid valves) separate each atrium and ventricle
The semilunar valves control blood flow to the aorta and the pulmonary artery.
42_06PathOfBloodFlow_A.html
THE EXTERNAL STRUCTURE:HUMAN HEART
THE INTERNAL STRUCTURE:HUMAN HEART
BLOOD FLOW THROUGH THE HEART
RED: OXYGENATED BLOOD -
BLUE: DEOXYGENATED BLOOD
CARDIAC CYCLE
The heart contracts and relaxes in a rhythmic cycle called the cardiac cycle
The contraction, or pumping, phase is called systole
The relaxation, or filling, phase is called diastole
The heart rate, also called the pulse, is the number of beats per minute
CARDIAC CYCLE
RED: OXYGENATED BLOOD -
BLUE: DEOXYGENATED BLOOD
ARTRIAL SYSTOLE
VENTRICULAR DIASTOLE
VENTRICULAR SYSTOLE
ARTRIAL DIASTOLE
CARDIAC CYCLE: CARDIOGRAM
RED: OXYGENATED BLOOD -
BLUE: DEOXYGENATED BLOOD
MAINTAINING THE HEART’S RHYTHMIC BEAT
Some cardiac muscle cells are self-excitable, meaning they contract without any signal from the nervous system
The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contract
Impulses from the SA node travel to the atrioventricular (AV) node
At the AV node, the impulses are delayed and then travel to the Purkinje fibers that make the ventricles contract
MAINTAINING THE HEART’S RHYTHMIC BEAT
Fig. 42-9-5
Signals spreadthroughoutventricles.
4
Purkinjefibers
Pacemakergenerates wave ofsignals to contract.
1
SA node(pacemaker)
ECG
Signals aredelayed atAV node.
2
AVnode
Signals passto heart apex.
3
Bundlebranches Heart
apex
WHAT WILL INFLUENCE THE HEART’S RHYTHMIC BEAT?
LYMPHATIC SYSTEM The lymphatic system returns fluid that leaks
out in the capillary beds This system aids in body defence Fluid, called lymph, re-enters the circulation
directly at the venous end of the capillary bed and indirectly through the lymphatic system
The lymphatic system drains into veins in the neck.
Lymph nodes are organs that filter lymph and play an important role in the body’s defence
Edema is swelling caused by disruptions in the flow of lymph.
LYMPHATIC SYSTEM
LYMPHATIC SYSTEM VS. CIRCULATORY -
DISEASES OF THE HEART AND CIRCULATORY SYSTEM
Cardiovascular diseases are disorders of the heart and the blood vessels
They account for more than half the deaths in the South Africa
One type of cardiovascular disease, atherosclerosis, is caused by the build-up of plaque (fat) deposits within arteries.
A heart attack is the death of cardiac muscle tissue resulting from blockage of one or more coronary arteries
A stroke is the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head.
Hypertension, or high blood pressure, promotes atherosclerosis and increases the risk of heart attack and stroke.
Hypertension can be reduced by dietary changes, exercise, and/or medication
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