Science Study Notes

2.1 Plant and animal cells

2.2 observing plant and animal cells through a microscope

2.3 the importance of cell division

Cell division is important because it is the way healthy body cells are expected to function and aid in the growth of different body parts.. Without cell division the body dies.

2.5 the cell cycle

2.7 cell division gone wrong

Cancer cells are cells gone wrong — in other words, they no longer respond to many of the signals that control cellular growth and death. Cancer cells originate within tissues and, as they grow and divide, they diverge ever further from normalcy. Over time, these cells become increasingly resistant to the controls that maintain normal tissue — and as a result, they divide more rapidly than their progenitors and become less dependent on signals from other cells. Cancer cells even evade programmed cell death, despite the fact that their multiple abnormalities would normally make them prime targets for apoptosis. In the late stages of cancer, cells break through normal tissue boundaries and metastasize (spread) to new sites in the body.

2.9 specialized cells

Specialized cells perform specialized functions in multicellular organisms. Groups of specialized cells cooperate to form a tissue, such as a muscle. Different tissues are in turn grouped together to form larger functional units, called organs. Each type of cell, tissue, and organ has a distinct structure and set of functions that serve the organism as a whole. Some of the specialized cells are fat cells, muscle cells, red blood cells.

3.1 animal tissues

Epithelium - Tissues composed of layers of cells that cover organ surfaces such as surface of the skin and inner lining of digestive tract: the tissues that serve for protection, secretion, and absorption.
Connective tissue - As the name suggests, connective tissue holds everything together. Some people consider Blood a connective tissue. These tissues contain extensive extracellular matrix.
Muscle tissue - Muscle cells contain contractile filaments that move past each other and change the size of the cell. Muscle tissue also is separated into three distinct categories: visceral or smooth muscle, which is found in the inner linings of organs; skeletal muscle, which is found attached to bone in order for mobility to take place; and cardiac muscle which is found in the heart.
Nervous tissue - Cells forming the brain, spinal cord and peripheral nervous system.

3.2 stem cells and cellular differentiation

The discovery of mouse embryonic stem (ES) cells >20 years ago represented a major advance in biology and experimental medicine, as it enabled the routine manipulation of the mouse genome. Along with the capacity to induce genetic modifications, ES cells provided the basis for establishing an in vitro model of early mammalian development and represented a putative new source of differentiated cell types for cell replacement therapy. While ES cells have been used extensively for creating mouse mutants for more than a decade, their application as a model for developmental biology has been limited and their use in cell replacement therapy remains a goal for many in the field. Recent advances in our understanding of ES cell differentiation, detailed in this review, have provided new insights essential for establishing ES cell-based developmental models and for the generation of clinically relevant populations for cell therapy.

3.3 the digestive system

3.4 the circulatory system

Diseases of the circulatory system

ne of the most common diseases of the circulatory system is arteriosclerosis, in which the fatty deposits in the arteries causes the walls to stiffen and thicken the walls. The causes are too much fat, cholesterol and calcium. This can restrict blood flow or in severe cases stop it all together, resulting in a heart attack or stroke.
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