punctuality no one is to be later than me. homework to be returned punctually. cleanliness

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


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


Unicellular and Simple organisms

Multicellular organisms

Simple diffusion is sufficient for exchange of materials

Simple diffusion cannot service the cells deep in

tissue layers.


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?


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.


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.


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?


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

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


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.


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


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


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.


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



Haemoglobin• Unbound state haemoglobin has

HIGH AFFINITY for oxygen.

• Binds to oxygen easily.

• Reversible process. How is it reversible?

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


b. Carbon dioxide

CO2 diffuse into blood plasma

Converted to HCO3- ions

HCO 3-CO

2


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


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

punctuality no one is to be later than me. homework to be returned punctually. cleanliness

Documents

simple taskthe need

simple diffusionthe

blood pressure

system of channels

unicellular organisms

heart valves

lymphatic system

system of tubes