punctuality no one is to be later than me. homework to be returned punctually. cleanliness
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Class Rules. Punctuality No one is to be later than me. Homework to be returned punctually. Cleanliness Courtesy If you need to speak, raise your hands. If someone is speaking, open your ears, and not your mouth. Consistency You must always have your notes with you. Commitment - PowerPoint PPT PresentationTRANSCRIPT
1. Punctuality
a. No one is to be later than me.b. Homework to be returned punctually.
2. Cleanliness
3. Courtesya. If you need to speak, raise your hands.b. If someone is speaking, open your ears, and not your mouth.
4. Consistencya. You must always have your notes with you.
5. Commitmenta. If you are tasked to do something, I expect it to be done with all your
effort.
Class Rules
Transport in Humans
Chapter Overview
9.1 The Circulatory System - Introduction & Anatomy
9.2 The Tissue Fluid 9.3 The Cardiac Cycle 9.4 Heart Diseases
9.1.1 The need for transport
9.1.2 Double Circulation
9.1.3 Veins and Arteries
9.1.4 The Heart
9.2.1 Components of the Tissue Fluida) Blood Plasmab) Red Blood Cellsc) White Blood Cellsd) Platelets
9.2.2 Exchange of Substances and The Lymphatic System
9.2.3 Haemoglobin
9.2.4 Rejection and ABO Blood Group
9.4.1 Myocardial infarction
9.4.2 Causes of Heart Diseases
9.3.1 Blood Pressure
9.3.2 Heart valves, Systole and Diastole
Transport in Mammals
Learning Objectives
By the end of the lesso
n, you should be able to:
i)*Describe the circulatory syste
m as a system of tu
bes with a
pump and valves to ensure one-way flow of blood.
ii)*Describe the double circulation in terms of a low pressu
re
circulation to the lungs and a high pressure circulation to the
body tissues and relate these differences to
the different
functions of the tw
o circuits.
iii)Describe the str
ucture and function of the heart in
terms of
muscular contraction and the working of valves.
iv)Identify the main blood vesse
ls to and fro
m the heart, lungs,
liver and kidney.
v)Describe the str
ucture of arteries, veins and capillaries in
relation to their functions and be able to recognize these
vessels fr
om photomicrographs.
Introduction
As an organism grows….
Introduction
It also needs to remove waste and carbon dioxide….
For unicellular or simple organisms, getting food and removing waste is a
rather simple task…
The Need for Transport
Unicellular and Simple organisms
All they rely on is….
SIMPLE DIFFUSION
The Need for Transport
What makes simple diffusion a reliable mechanism in unicellular organisms?
Here are two important factors:
1. Surface Area to Volume Ratio
2. Maintaining a Steep Diffusion gradient
The Need for Transport
Unicellular and Simple organisms
Multicellular organisms
Simple diffusion is sufficient for exchange of materials
Simple diffusion cannot service the cells deep in
tissue layers.
The Need for Transport
Multicellular organisms thus cannot depend on simple diffusion because they have:
1. LARGE Surface Area to Volume Ratio
2. DIFFICULTY in maintaining a STEEP Diffusion gradient
How could they solve these problems?
The Need for Transport
Thus, multicellular organisms found a strategy to solve the problem of access to
dissolved gases and removal of waste.
They develop a system of channels that service cells that are deep in the body of the organism.
This system of channels increases theSurface Area to Volume Ratio, thus allowing
substances to be transported quickly.
The Need for Transport
Sponges are simple organisms with channels and sinuses.Water from the environment enters from tiny pores and exits from a big opening at
the top of each column of a sponge.
The Need for Transport
Jellyfishes has a highly branched gastrovascular cavity which services cells in the deeper regions of the bell.
Gastrovascular Cavity
Mouth/Anus
Oral Arms
Bell
• The simple transport system of the jellyfish and sponge may suffice for small organisms.
• However, in bigger organisms this would be inefficient. Why is that so?
The Need for Transport
Blood
Common Features of Circulatory Systems
1. A fluid to transport metabolites
2. A network of chambers and sinuses
3. A means of generating current
VesselsHeart
• Before we examine the mammalian circulatory system, what are the common features in the circulatory system of the jellyfish and sponge?
• Big terrestrial organisms such as mammals also possess the following features. However, they need a more efficient pump…
Human Circulatory System
Heart
Vessels
Single and Double Circulation
Single and Double Circulation
Single and Double Circulation
Advantages of Double Circulation System
1. Blood entering pulmonary circulation at low pressure gives time for uptake of oxygen and removal of carbon dioxide.
2. Blood leaving the left ventricle at high pressure Quickly delivers oxygenated blood to rest of the body.
Structure of the Mammalian Heart
The left ventricle has a more
muscular wall than the right
ventricle. This allows the heart
to pump blood at great
pressures so as to bring blood
to the extremities of the body.
The right atrium receives
deoxygenated blood directly
from both the superior and
the inferior vena cava.
The right ventricle also has muscular walls, but are relatively thinner than the left ventricle as it only needs to pump blood to the pulmonary circulation.
The Heart ChambersThe left atrium receives oxygenated
blood directly from the pulmonary
veins. The bicuspid valve separates
the left atrium from the left ventricle.
The Heart Valves
Structure of the Mammalian Heart
The bicuspid valve or mitra
l valve
consists of two flaps that point into the
left ventricle. It opens to allow blood to
flow from the left atriu
m to the left
ventricle.
Semi-lunar valves are found
at the base of the pulmonary
artery and the aorta to
prevent backflow of blood.
The tricuspid valve separate the right atrium from the right ventricle. It consists of three flaps which point into the right ventricle. Tendons connect these flaps to the walls of the right ventricle.
Structure of the Mammalian Heart
The superior and inferior vena
cava are two large veins that
collect and return deoxygenated
blood to the right atrium.
The aorta is a large artery, through which blood from the left ventricle leaves the heart. It is thick and muscular in order to withstand the high blood pressure which results from the contraction of the left ventricle.
The Main Vessels
Structure of the Mammalian Heart
The left and right pulmonary
vein brings oxygenated blood
from both lungs back into the
heart via the left atrium.
The pulmonary artery brings
deoxygenated blood from the right
ventricle to the lungs. It branches
off to the left and the right lungs
upon leaving the heart.The Main Vessels
The median septum is a muscular wall that separates
the left side of the heart from the right side of the heart.
The Median Septum
Structure of the Mammalian Heart
Features FunctionsPresence of median septum
Separates oxygenated from deoxygenated blood
Presence of AV valves and semi-lunar valves
Prevent backflow and ensures blood flows in one direction
More muscular walls of left ventricle
To deliver blood to the extremities of the body
Pericardial fluid Reduces friction as the heart moves against the lungs
The Blood Vessels
There are 5 types of vessels in the mammalian circulatory system.
1. Arteries2. Arterioles3. Veins4. Venules5. Capillaries
The Blood VesselsArteries Structure• 3 layers of tissues
• Thick elastic, muscular walls
withstand high blood pressure recoil and stretch to push blood along
• Smooth muscles contract or dilates lumen constrict or dilate thus controlling blood flow
The Blood Vessels
Veins Structure
• 3 layers of tissues
• Less elastic, muscular walls
• Presence of valves prevent backflow of blood
The Blood Vessels
Capillaries Structure• Walls are only one-cell thick
facilitate rapid diffusion
• Highly branched increase SA/V ratio compared to arteriole from which the branches originate.
Comparing the Blood Vessels
Features Arteries Veins CapillariesDirection of blood flow
Away from Heart Towards Heart Arteriole Venules
Blood Oxygenated (except in pulmonary and umbilical arteries)
Deoxygenated(except in pulmonary and umbilical veins)
Oxygenated Deoxygenated
Blood Pressure Highest Lowest High LowWall Structure Thick, elastic muscular Relatively thinner, less
muscularOne-cell thick
Lumen Ø Smaller compared with vein of same Ø
Wider compared with vein of same Ø
Small enough only for 1 RBC to squeeze through
Valves Absent Present Absent
Components of Blood
(2%)
1. Plasma – 55% total volume of blood mostly liquid water (91%) soluble blood proteins (7%) hormones electrolytes nutrients
2. Cellular Component – 45% total volume of blood White blood cells Platelets Red blood cells
Components of BloodRed Blood Cells (Erythrocytes)
1. Biconcave, circular, flattened discs Increase surface area to volume ratio
2. Lack nucleus To carry more haemoglobin
3. Elastic To move through capillaries
4. Possess haemoglobin To transport oxygen
Components of BloodWhite Blood Cells (Leucocytes)
Two groups of leucocytes:1. Lymphocytes
Formed in bone marrows and mature in lymph node Typically round with rounded nucleus Produces antibodies that fight against pathogens
2. Phagocytes Many types, shapes and sizes Granular with lobed nucleus Ingests foreign bodies by phagocytosis
Components of Blood
Platelets (Thrombocytes)
1. Not true cells; cytoplasmic fragments2. Critical role in the clotting of blood
(to be discussed later)
Functions of Blood1. Transport
a. Oxygenb. Carbon Dioxidec. Foodd. Hormonese. Waste
2. Protectiona. Production of antibodiesb. Phagocytosis of foreign bodiesc. Clotting of blood (prevent loss of blood)
3. Distribute body heat
We shall first look at the details of blood as an agent
for the transport of materials.
Functions of Blood1. Transport
a. Oxygen – The Role of Haemoglobin
Haemoglobin• A protein complex that contains 4 iron atoms• Gives blood its red colour• Able to bind to oxygen molecules• In the unbound state, haemoglobin is a
deep purplish red.• When oxygen is bonded, haemoglobin turns
into a bright red oxyhaemoglobin.
Fe
Fe
Fe Fe
Fe
Fe
Fe Fe
Functions of Blood1. Transport
a. Oxygen – The Role of Haemoglobin
Haemoglobin• Unbound state haemoglobin has
HIGH AFFINITY for oxygen.
• Binds to oxygen easily.
• Reversible process. How is it reversible?
Functions of Blood1. Transport
a. Oxygen – The Role of Haemoglobin
Fe
Fe
Fe Fe
O2
O2
O2
O2
Functions of Blood
– The Role of Haemoglobin1. Transport
a. Oxygen
• Dissociation of O2 occurs when RBCs with HbO enters oxygen poor tissues
Body TissuesRed Blood Cell
Functions of Blood1. Transport
b. Carbon dioxide
CO2 diffuse into blood plasma
Converted to HCO3- ions
HCO 3-CO
2
Functions of Blood1. Transport
c. Foodd. Hormonese. Waste
Examples• Glucose• Amino Acids• VitaminsChemical messengers that control
many metabolic processes.
Examples• Insulin• Glucagon• Adrenalin
Excretory products delivered to the kidneys for removal.
Examples• Urea• Uric Acid• Creatinine
Functions of Blood1. Transport
a. Oxygenb. Carbon Dioxidec. Foodd. Hormonese. Waste
2. Protectiona. Production of antibodiesb. Phagocytosis of foreign bodiesc. Clotting of blood (reduce loss of blood)
3. Distribute body heat
2. Protectiona. Production of antibodies
So we have seen how blood transports metabolic substances and the
important role played by haemoglobin….
Next, we shall look at the protective functions of blood.
• Antibodies are soluble proteins…
• Mostly produced by lymphocytes.
• Capable of recognizing foreign objects…
• Then binds to them…
• Foreign objects with antibodies bounded to them are
destined for destruction by immune system.
Functions of Blood
2. Protectiona. Production of antibodies
• Phagocytes are able to ingest foreign particles.
• Forms pus at wounded sites.
Functions of Blood
2. Protectionb. Phagocytosis of foreign bodies
• Serves to prevent excessive blood loss• Serves to reduce infection by pathogens• 3 steps involved:
• Damaged tissues and platelets release thrombokinase.
• Prothrombin Thrombin
• Fibrinogen Fibrin
Functions of Blood
2. Protectionc. Clotting of blood (reduce loss of blood)
ABO Blood Groupings
Lymphatic System
Movement of Blood Plasma into Body Tissues• Blood in arterioles Higher pressure than capillaries
• Blood plasma hence forced to leave capillaries
• And enter body tissues
• Soluble proteins cannot pass through capillaries.
• Hence the fluid that enters the body tissues does not
contain these proteins.
• This fluid is known as interstitial fluid or tissue fluid.
Lymphatic SystemWhere does interstitial fluid goes?• Collected in lymph vessels.
• Part of the lymphatic system.
Lymphatic System
Where does interstitial fluid goes?• Returned back to bloodstream via left subclavian vein
Cardiac Cycle
Cardiac Cycle• Is the sequence of contraction and relaxation of the atria and
ventricles.
• Systole = contraction
• Diastole = relaxation
• May be divided into
3 phases.
Cardiac Cycle
Cardiac Cycle
Phase 1 Atrial Systole
Phase 2Ventricular Systole
Phase 3Ventricular Diastole
Systole: Atrial Ventricular -
Diastole: Ventricular Atrial Atrial and Ventricular
Blood Pressure
Atria > Ventricles Ventricles > Pulmonary Artery/ Aorta
Pulmonary Artery/ Aorta > Ventricles
Valves AV valves open AV valves closesSemi-lunar valves open
AV valves openSemi-lunar vlaves closes
Direction of Flow of Blood
Atria Ventricles Ventricles Pulmonary Artery/ Aorta
Pulmonary Artery/ Aorta to Lungs/ Rest of body
Coronary Heart Diseases
Coronary Heart Diseases (CHD)
• Many possible causes, but most due to atherosclerosis (Watch video)
• Symptoms: (1) Angina pectoris; (2) Myocardial Infarction
• Risk Factors: (1) Unbalanced diet(2) Smoking(3) Diabetes(4) Lack of exercises(5) Stress