CARDIAC PHYSIOLOGY
LEARNING OUTCOMES
Anatomy of the Heart
Cardiac excitation
Cardiac contraction and Circulation
Electrocardiogram and cardiac axis
Rate or rhythm
Sympathetic influences on cardiac contraction
Pharmacology, exercise & modified Valsalva
CARDIAC ANATOMY
Primary function of the heart is to deliver substrate, hormones and oxygenated blood to the organs (and
cells) and help remove by-products of metabolism (including carbon dioxide)
- The only job of heart is to deliver blood it doesn’t really do anything else
- Delivers substrates- whatever the body is utilising for energy e.g. fats, glucose – delivers to
wherever it is needed
- Also delivers hormones which releases from one area of the body but has an impact on another
area of the body
- blood is basically the medium on how they travel
- Most importantly it also delivers oxygen to the organs that need it and removes metabolic bi
products via kidneys etc
- The most important organ that the heart supplies besides its own self is the brain.
o The brain has no reserves to fall back on it needs constant supply of oxygen and substrates
in order to survive, that’s why even a small fall in the bloody supply because of stroke or
heart problems becomes a big issue for the brain.
o Initially you pick up neurological symptoms e.g. might feel dizzy or light-headed but then
if things progress then you could have paralysis or even death
- The heart basically sits in the middle of the chest cavity at the centre- centre-left of the chest
cavity, behind the sternum
- Heart sits above the diaphragm (at the base)
- Lungs on either side of the heart
- Sternal angle at manubriosternal joint and right behind that is the top part of your heart. Heart lies
immediately behind the breastbone
, Cardiac tissue has basic layers:
- most inside layer of the heart is called endocardium made up the same tissues and cells which are
on the insides of the blood vessels.
The middle part of the heart tissue. The muscle called myocardium it’s made up of striated, mono
nucleated cardiomyocytes, rich in mitochondria
o The heart works constantly throughout our life so its rich in mitochondria- depends on
oxidative metabolism – but it constantly works
The pericardium has two layers:
o The
one
attached
right to the
myocardium is called the visceral pericardium
o The one on the outside is called parietal pericardium
o They’re fibrous layers and right between them there is very clear liquid which surrounds the
heart, so the heart sits inside surrounded by this liquid and right outside this liquid it this the
fibrous layer part.
pericardial cavity and is filled with pericardial fluid
o This fibrous layer attaches to the blood
vessels and the heart floats inside it. It is
really important that this fluid is
present so that there’s less friction going
on when the heart is actually beating
o The volume of the ultraclean plasma is
usually 40-50ml- and acts as a
lubricant
LEARNING OUTCOMES
Anatomy of the Heart
Cardiac excitation
Cardiac contraction and Circulation
Electrocardiogram and cardiac axis
Rate or rhythm
Sympathetic influences on cardiac contraction
Pharmacology, exercise & modified Valsalva
CARDIAC ANATOMY
Primary function of the heart is to deliver substrate, hormones and oxygenated blood to the organs (and
cells) and help remove by-products of metabolism (including carbon dioxide)
- The only job of heart is to deliver blood it doesn’t really do anything else
- Delivers substrates- whatever the body is utilising for energy e.g. fats, glucose – delivers to
wherever it is needed
- Also delivers hormones which releases from one area of the body but has an impact on another
area of the body
- blood is basically the medium on how they travel
- Most importantly it also delivers oxygen to the organs that need it and removes metabolic bi
products via kidneys etc
- The most important organ that the heart supplies besides its own self is the brain.
o The brain has no reserves to fall back on it needs constant supply of oxygen and substrates
in order to survive, that’s why even a small fall in the bloody supply because of stroke or
heart problems becomes a big issue for the brain.
o Initially you pick up neurological symptoms e.g. might feel dizzy or light-headed but then
if things progress then you could have paralysis or even death
- The heart basically sits in the middle of the chest cavity at the centre- centre-left of the chest
cavity, behind the sternum
- Heart sits above the diaphragm (at the base)
- Lungs on either side of the heart
- Sternal angle at manubriosternal joint and right behind that is the top part of your heart. Heart lies
immediately behind the breastbone
, Cardiac tissue has basic layers:
- most inside layer of the heart is called endocardium made up the same tissues and cells which are
on the insides of the blood vessels.
The middle part of the heart tissue. The muscle called myocardium it’s made up of striated, mono
nucleated cardiomyocytes, rich in mitochondria
o The heart works constantly throughout our life so its rich in mitochondria- depends on
oxidative metabolism – but it constantly works
The pericardium has two layers:
o The
one
attached
right to the
myocardium is called the visceral pericardium
o The one on the outside is called parietal pericardium
o They’re fibrous layers and right between them there is very clear liquid which surrounds the
heart, so the heart sits inside surrounded by this liquid and right outside this liquid it this the
fibrous layer part.
pericardial cavity and is filled with pericardial fluid
o This fibrous layer attaches to the blood
vessels and the heart floats inside it. It is
really important that this fluid is
present so that there’s less friction going
on when the heart is actually beating
o The volume of the ultraclean plasma is
usually 40-50ml- and acts as a
lubricant
