Term 4

The Scope of the Discussion

Concepts of Respiratory medicine

Concepts of Cardiovascular medicine

Chest X-ray for Cardiovascular & Respiratory purposes

Cells need O2

Why?

Because cells need energy

Therefore they need to produce ATP

To produce ATP, cells need O2

Why ATP?

It’s the universal energy source

What does that mean?

Every cell can use ATP for their energy needs

Cells need O2

How do we produce ATP from O2?

Electron Transport Chain

In the inner mitochondrial membrane

Does that mean cells that don’t have mitochondria can not

produce ATP?

Yes, they can’t

What are the examples? mature human RBC

How do they survive?

They rely on ATP produced by other cells

How do they get ATP from other cells?

Via blood

Bottom line is,

Almost all the cells need O2

There should be a way to get O2 from the environment & deliver it to

each & every single cell in the body.

(It’s like ordering a pizza & getting it delivered to your

doorstep)

Human body basically needs 2 major things to complete this

process

Respiratory system & Cardiovascular system

Respiratory

System

Process of Respiration

VentilationGas

exchangeGas

TransportCellular

Respiration

Ventilation

Expansion of thoracic cavity (Diaphragm/IC muscles)

What is Pleura & Pleural cavity

Boyles Law acting inside it

Bulk flow gases

Inspiration (Active) & Expiration (Passive*)

What is ventilatory failure? (not respiratory failure)

Air way restriction, Fibrosis & Paralysis can compromise process

of ventilation

Gas Exchange Before going there we need to recap some basic kinetic physics

Is there a pressure inside a vacuum. NO. Why?

Because there are no molecules to create a pressure. NO molecules to collide & therefore no pressure created.

Now let’s think about air.

Air is a mixture of gases. (N2/O2/CO2 & other)

Total pressure of air = Sum of pressures created by individual gas

Pressures created by individual gas is called “Partial pressure of that gas”

In other words, the particular gas’s contribution to the total pressure.

SO why are we concerned about these individual pressures rather than the total pressure?

Because pressure created by some people matters to us rather than pressure created by others even though how great that the magnitude is.

(Pressure created by girlfriend vs pressure created by lecturers)

Gas Exchange

Partial pressure of O2 & partial pressure of CO2 are way more important to human bodies & therefore to us, medical

students & doctors who are trying to figure out what’s happening inside.

PaO2 is to indicate partial pressure of Oxygen

PaCO2 is to indicate partial pressure of CO2

Gas Exchange

Alveolar Capillary Membrane

Diffusion capacity of gases

A-A Gradient

Diseases affecting gas exchange

- IRDS & ARDS

- Pulmonary oedema* (Heart failure, Pneumonia)

-

* J cells

Gas Exchange

Pulmonary & Systemic circulation

Sup. & Inf. Vena cava

Right atrium

Tricuspid valve

Right Ventricle

Pulmonary Arteries

Pulmonary Capillaries

Pulmonary Veins

Left Atrium Mitral Valve

Left Ventricle

Aorta

Systemic Circulation

Ventilation & Perfusion

Has to be complimentary (or Matched) – Why?

Normal variation in lung

Concept of Shunt & Dead Space

Speaking of Dead Space….What do you understand by

dead space?

Back to those concepts

Cyanosis

Diseases causing V/Q mismatch

In Blood?

“PaO2” ……?

O2 saturation…..?

Hb-O2 Curve

Meaning of right & left shift

Stories (fever/HARA)

Cyanosis again

Cellular respiration & CN poisoning

Regulation

Mainly Neural

Altered by PaO2, [H+] & PaCO2

How?

Central & Peripheral chemo receptors?

E.g. – Exercise/ High altitudes/ Metabolic

Neurological failure

Sleep Apnoea?

Respiratory Adjustments

Exercise

High altitudes

Metabolic (Acidosis/Alkalosis)

- DM

- CRF

-

Respiratory Diseases

Infections (Respiratory tract & Lung)

Obstructive diseases

Restrictive diseases (more correctly Interstitial lung diseases)

Pulmonary vascular diseases

Tumors of the Lung & Bronchus

Diseases of Pleura, Diaphragm & Chest Wall

Respiratory failure…..???

Respiratory Failure

Respiratory failure

Type 1Diffusion Problems

Type 2VentilatoryProblems

Any Questions…?

Topics we have covered

Process of Respiration

Regulation of Respiration

Respiratory adjustments

Respiratory diseases

NOTE: Always get used to look back & summarize what’s been

said, discussed or learned.

Cardiovascular

System

Topics

Heart

- Anatomy (Gross/Histologic)

- Conducting system

- Cardiac cycle

Vascular system

- Blood pressure

- Circulation in heart/brain/skin/GI tract

- Renal circulation

Recap - Anatomy

Gross – 4 chambers/4 valves/3 layers/ 2 vessels

Murmurs & other effects of valvular lesions

Coronary circulation

MI/IHD

Histology – 2 types of cells

1. Cardiac myocytes (functionally similar)

2. Specialized myocytes (lack contractile properties/ different action potentials ć

long RF period)

Conducting System

SA node 3 inter-nodal

pathways AV node

Bundle of His

L & R bundle

branches

Purkinje system

Conducting System

Made up of specialized myocytes

Capable of spontaneous discharge

At different ratese.g.:- SA node 70, AV node 40, PK sys 20

Conducting System

Vagus nerve

(-)Baroreceptors

Circulating catecholamin

es

(+)

Adrenal cortex

Arrhythmias

Arrhythmias

Brady

< 60 bpm

Sinus bradycardia

Heart Blocks

Tachy

> 100 bpm

Sinus tachycardia

Supraventricular

tachycardias

Ventricular tachycardia

Sinus Bradycardia

Sinus bradycardia

Physiological

(Normal)

Sleeping

Athletes

β - Blockers

Pathological

(Abnormal)

Sick sinus syndrome

Jaundice

Myxoedema

Hypothermia

Heart Blocks

Heart blocks

1st Degree

2nd Degree

Morbitz

type 1

Morbitz

type 2

3rd Degree

(Complete)

• Causes…?

Sinus Tachycardia

Sinus Tachycardia

Physiological

(Normal)

Exercise

Anxiety

Pathological

(Abnormal)

Anaemia

Fever (Hyperthermia)

Thyrotoxicosis

Hypothermia

Tachycardia

Tachycardia

Supraventricular*Atrial Flutter

Atrial Fibrillation*

VentricularVentricular Tachycardia

Ventricular Fibrillation*

Arrhythmias

Two main problems in arrhythmias

1. ↓ Cardiac output

2. Stasis of blood (Thomboembolisms)

Mx

BradycardiasPace-makers

Rx of cause

Tachycardiasβ Blockers

Defibrillator

ECG

Therapeutic Procedures

Cardiac catheterization & stenting

Valve replacement

CABG

Transesophageal sonography

Pacemakers

Radiofrequency ablation

DC cardioversion (Defibrillation)