Physiology: is the science that deal with the study of the
function of the healthy living organisms and the changes that
occurs during activity.
The goal of physiology: is to explain the physical and chemical
factors that are responsible for the origin, development, and
progression of life. Each type of life, from the simple virus to the
largest tree or the complicated human being, has its own functional
characteristics. Therefore, the vast field of physiology can be
divided into viral physiology, bacterial physiology, cellular
physiology, plant physiology, human physiology, and many more
subdivisions.
Human Physiology: In human physiology, we attempt to
explain the specific characteristics and mechanisms of the human
body that make it a living being.
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Reconstruction of a typical cell, showing the internal
organelles in the cytoplasm and in the nucleus.
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Organelle Function
Nucleus Stores genetic information
Nucleolus Makes ribosomes
Cytoplasm Contains the contents of the cell
Cytosol Gel-like matrix that holds water and nutrients
Cytoskeleton Structure, support and transport
Ribosome Makes protein
Rough Endoplasmic
Reticulum Makes proteins for the endomembrane system
Smooth Endoplasmic
Reticulum Detoxifies the cell and makes lipids
Golgi Apparatus Sorts proteins
Mitochondria Makes energy
Lysosome Removes unwanted material and waste
Peroxisome Regulate biochemical pathways that involve
oxidation
Vacuoles Store water and nutrients
Vesicles Transport materials around the cell
Cell Membrane A thin flexible barrier that separates the cell
from its environment
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Cells as the Living Units of the Body
The basic living (functional) unit of the living organism is the cell.
Why? Because:
1- Most of the basic life processes are carried out at the cellular
level.
2- The human body contains many different kinds of cells, each of
which has characteristic shape and size and a particular function
to perform.
Each organ is an aggregate of many different cells held together
by intercellular supporting structures. Each type of cell is specially
adapted to perform one or a few particular functions.
The many cells of the body often differ markedly from one another;
all of them have certain basic characteristics that are alike. EX,
1- In all cells, oxygen reacts with carbohydrate, fat, and protein to
release the energy required for cell function.
2- Further, the general chemical mechanisms for changing
nutrients into energy are basically the same in all cells.
3- All cells deliver end products of their chemical reactions into the
surrounding fluids.
4- Almost all cells also have the ability to reproduce additional cells
of their own kind except neurons.