THE HEART - INSIDE THE HEART, MUSCLE STRUCTURE,

1. THE HEART

2.  The heart is the engine at the centre of the body’s
circulation system. It starts working even before
we are born and from then on, it beat constantly,
throughout our lives.
 Made from a special kind of muscle not found
anywhere else in the body, the hardworking heart
contracts and relaxes about 70 time a minute.

4. THE MIGHTY MUSCLE:
 A healthy adult’s heart is about the size of a
clenched fist, it sits in the thorax (chest), and in
most people have the tip points towards the left
side of the body.

5. MUSCLE STRUCTURE:
 There are 3 types of muscle tissue are cardiac,
smooth, and skeletal. Cardiac muscle cells are
located in the walls of the heart, appear striped
(striated), and are under involuntary control.
 This cross section of heart muscle shows that the
structure is a network of interlocking fibers. The
oval discs are mitochcondria, which supply the
muscle cells with energy they need.

6. INSIDE THE HEART:
 The heart is really 2 pumps in one, working in a
continuous cycle. The right side pumps blood to the
lungs, while the left side receives blood back from the
lungs, then it sends it round the rest of the body.
 The heart pumps out cupful of blood about 70 times a
minute, speeding up when necessary to meet the body
cells’ increased demand. Over a lifetime, the heart
beat 2.5 billion times without resting.