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

2. Learning Outcomes o Somatic cells form different types of body tissue. Epithelial cells cover the body surface and line body cavities, connective tissue includes blood, bone and cartilage cells, muscle cells form muscle tissue and nerve cells form nervous tissue. o The body organs are formed from a variety of these tissues. During cell division the nucleus of a somatic cell divides by mitosis to maintain the diploid chromosome number. Diploid cells have 23 pairs of homologous chromosomes.

3. Somatic cells Somatic cells are the differentiated cells that form the different types of body tissue that exist.

4. Somatic cells B Lymphocyte Hyaline cartilage Smooth muscle

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

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

7. Increasing Level Of Complexity Cells  Tissues  Organs  Systems  Organism

8. Questions 1.Name three different types of differentiated tissue derived from somatic cells in addition to connective tissue. 2.Arrange the following terms in order of increasing complexity: body, cell, organ, system, tissue. 3.Briefly describe how chromosome number is maintained in a somatic cell at cell division.

9. Answers 1.Epithelial, bone, cartilage, muscle (Any 3 of). 2.Cell  Tissue  Organ  System  Body 3.Before nuclear division, the genetic material in a cell undergoes replication and becomes doubled. This is followed by nuclear division and the genetic information is divided equally between the two daughter nuclei. Therefore each somatic cell formed receives an identical copy of the full set of 46 chromosomes (23pairs).