1. Differentiation in Somatic Cells
Higher Human Biology
Unit 1 – Sub-Topic 1 (b)

2. Learning Intention
To discuss what somatic cells are and cells that arise from the differentiation of somatic cells.

4. Somatic cells – What is a somatic cell?
B Lymphocyte
Smooth muscle
Hyaline cartilage

5. Somatic cells - examples
Ciliated epithelial cell
neutrophil
Red blood cell
platelets

6. Somatic cells - examples
Cardiac muscle
Squamous epithelial cells
T lymphocyte
Nerve cells

7. Somatic cells divide by mitosis to form more somatic cells
Somatic cells are the differentiated cells that form the different types of body tissue that exist.
Somatic cells divide by mitosis to form more somatic cells
Somatic cells are produced by cellular differentiation where a cell develops more specialised functions by expressing the specific genes needed for each cell type.
Please see comments in Teacher notes regarding protein expression

8. Tissues and organs
Body organs are formed from a variety of tissues made from
somatic cells. E.g.
Epithelial cells which cover the body surface and line body cavities (E.g bladder, respiratory etc)
Connective tissue includes blood, bone and cartilage cells
Muscle cells form muscle tissue
Nerve cells form nervous tissue

9. proteins characteristic for that type of cell.
Once a cell becomes differentiated it only expresses the genes that produce the
proteins characteristic for that type of cell.
DON’T MEMORISE.
Remember that specialised blood cells are produced by cell division ( mitosis) and gradually become different as they specialise by:-
Differentiation
specialised genes being switched on for each cell type
only making specialised proteins to help them perform their function

10. Think…………
Can you name a specialised protein in each of the somatic cells below?
Red Blood Cell
Phagocyte
Lymphocyte
Thrombocycte

11. Give an account, with examples, of the different body tissue types and their functions. (8 marks)
Body tissue cells derive from somatic stem cells …
by repeated mitosis.
Epithelial tissue - covers the organ surfaces.
Protection - skin / secretion - intestinal glands / absorption - villi.
Connective tissue - gives shape to organs and supports them.
Protection - skull bones / structural framework - ribs / storage of energy - adipose tissue / connecting body organs - blood / connecting epithelial to muscle tissue - cartilage (in tendons)
Muscle tissue - which causes locomotion or movement within organs.
Skeletal muscle - locomotion / smooth muscle - in arterioles control of access to capillary bed / cardiac muscle - contraction of the heart.
Nervous tissue - which transmits messages between the central nervous system and the rest of the body (and within the central nervous system).
Neurons - conduct impulses / glial cells - maintain a constant environment for neurons.

12. Learning Outcomes
Somatic cells divide by mitosis to form more somatic cells.
(b) Cellular differentiation is the process by which a cell develops more specialised functions by expressing the genes characteristic for that type of cell.
(c) Once a cell becomes differentiated it only expresses the genes that produce the proteins characteristic for that type of cell.