Youtube link: https://youtu.be/9afZppodmZ0 Human Cell

1. RADIOBIOLOGY
The Human Cell,Tissues and Organs
Rahman Ud Din
Senior Lecturer Radiology
Northwest Institute of Health Sciences

2. LEARNING OUTCOME
 The basic building block
 What is cell?
 Cell’s components
 Cell membrane
 Cell nucleus
 Mitochondria
 Golgi bodies
 Endoplasmic reticulum etc.
 Effect of Radiation on cell
 Cell function
 Levels of Organization

3. THE HUMAN CELL
 Molecular component of
Human body made of
intricate cellular structure
 These cellular structure
ensures growth, development
and function

4. COMPONENTS OF A CELL
Nucleus
 The nucleus is an organelle found in human cells.
 Inside its fully enclosed nuclear membrane
 It contains the majority of the cell's genetic material.
 This material is organized as DNA molecules, along with a
variety of proteins, to form chromosomes.
 It also contains RNA and water molecules
Function of DNA
 The nucleus controls and regulates the activities of the cell
(e.g., growth and metabolism) and carries the genes,
structures that contain the hereditary information

5. Nucleolus
 The nucleolus is the distinct structure present in
the nucleus of eukaryotic cells.
 Primarily, it participates in assembling the
ribosomes
 Alteration of transfer RNA and sensing cellular
stress.
 The nucleolus is composed of RNA and proteins,
which form around specific chromosomal
regions.

6. Cell Membrane
 The cell membrane (also known as the plasma
membrane (PM) or cytoplasmic membrane)
 It is a biological membrane that separates the
interior of all cells from the outside environment (the
extracellular space) which protects the cell from its
environment.
 The cell membrane consists of a lipid bilayer,
including cholesterols that sit between phospholipids
to maintain their fluidity at various temperatures.
Function:
 Protection for a cell
 Transport of nutrients

7. Cytoplasm
 Cytoplasm is a thick solution that fills each
cell and is enclosed by the cell membrane.
 It is mainly composed of water, salts, and
proteins.
 In eukaryotic cells, the cytoplasm includes
all of the material inside the cell and
outside of the nucleus.

8. Endoplasmic Reticulum (connects DNA with
cytoplasm)
 Endoplasmic reticulum (ER), a continuous
membrane system that forms a series of
flattened sacs within the cytoplasm of
eukaryotic cells and serves multiple
functions, being important particularly in
the synthesis, folding, modification, and
transport of proteins .
 Two types
 rough endoplasmic reticulum (rough ER)
– proteins synthesis
 smooth endoplasmic reticulum (smooth
ER) -the synthesis and storage of lipids

9. Mitochondria
 Also known as engine of the cell
 Mitochondria are membrane-bound
cell organelles (mitochondrion,
singular) that generate most of the
chemical energy needed to power
the cell's biochemical reactions.
 Chemical energy produced by the
mitochondria is stored in a small
molecule called adenosine
triphosphate (ATP)

10. Ribosomes
 Protein synthesis
 Ribosomes are minute particles
consisting of RNA and associated
proteins that function to synthesize
proteins.
 Proteins are needed for many cellular
functions such as repairing damage or
directing chemical processes.
 Ribosomes can be found floating within
the cytoplasm or attached to the
endoplasmic reticulum.

11. Lysosomes
 Digesting enzymes)
 A lysosome is a membrane-bound cell
organelle that contains digestive enzymes.
 Lysosomes are involved with various cell
processes.
 Break down excess or worn-out cell parts.
 They may be used to destroy invading
viruses and bacteria.

12. LEVELS OF ORGANIZATION

13. EFFECTS OF IRRADIATION ON CELL
 The lethal dose for a single cell organism measured in kilorad
 Human cell can be killed with dose less than 100 rad (1 Gy)
 Physical characteristic of a cell is changes with (1 Mrad=10 kGy)
 Experiments shown nucleus is sensitive to radiations
 Microbeam of electron is used in experiments
 Focused and directed microbeam

14. CELL FUNCTION
 Nerve cells, blood cells and muscles cells are different from each other
 Each has specialised functions
 All cells absorb nutrients and uses for energy production
 And molecular synthesis
 Irradiation can cause cell death or malfunction
 Protein synthesis is a critical cellular function

15. THANK YOU