Published by Hodder Education © 2010 Helen McGuinness
1 Objectives
By the end of this chapter you will be able to recall and understand the following knowledge:
the different levels of structural organisation in the body
the importance of homeostasis and metabolism in correct body functioning
parts of a cell’s structure and their functional significance
Published by Hodder Education © 2010 Helen McGuinness
2 Objectives
the structure and function of the main tissue types in the body
the interrelationships between the cells and tissues and other body systems
common pathologies associated with cells and tissues.
Published by Hodder Education © 2010 Helen McGuinness
3 Key words
atommolecule
celltissueorgan
systemhomeostasismetabolism
cell membranecytoplasm
nucleusnucleolusnuclear
membranelysosomevacuole
ribosomeGolgi body
mitochondriacentrosomecentromere
centrioleschromatiddiffusionosmosisactive
transportfiltration
cell respirationtissue fluid
meiosismitosis
Published by Hodder Education © 2010 Helen McGuinness
4 Structural organisation of the body
The human body involves five levels of structural organisation – atoms and molecules, cells, tissues, organs and systems.
Atoms and molecules are the lowest level of organisational complexity in the body.
Cells are the smallest units that show characteristics of life.
Published by Hodder Education © 2010 Helen McGuinness
5 Structural organisationof the body
Tissues are a group of similar cells that perform a certain function.
Organs are tissues grouped into structurally and functionally integrated units.
Systems are a group of organs that work together to perform specific functions.
Published by Hodder Education © 2010 Helen McGuinness
6 Structure of a cell
A cell is the basic, living, structural and functional unit of the body.
The principal parts of the cell are the cell membrane and its organelles which play specific roles in cellular growth, maintenance, repair and control.
The cell membrane encloses the cell and protects its contents. It is semi-permeable and governs the exchange of nutrients and waste materials.
The nucleus controls the cell’s activities and contains the genetic information.
Published by Hodder Education © 2010 Helen McGuinness
7 Structure of a cell
The cytoplasm is the substance inside the cell between the plasma membrane and the nucleus.
The ribosomes are sites of protein synthesis. The endoplasmic reticulum links the cell
membrane with the nuclear membrane and assists movement of materials out of the cell.
Published by Hodder Education © 2010 Helen McGuinness
8 Structure of a cell
The Golgi body processes, sorts and delivers proteins and lipids (fats) to the plasma membrane, lysosome and secretory vesicles.
The lysosome is a round sac in the cytoplasm that contains powerful enzymes to help destroy waste and worn out cell materials.
The mitochondria are the ‘powerhouses’ of the cell.
Published by Hodder Education © 2010 Helen McGuinness
9 Structure of a cell
The centrosome is a dense area of cytoplasm, containing the centrioles.
The centrioles are paired small spherical structures associated with cell division, or mitosis.
The chromatids are a pair of identical strands that are joined at the centromere and separate during cell division.
The centromere is the portion of a chromosome where the two chromatids are joined.
Published by Hodder Education © 2010 Helen McGuinness
11 Functions of cells
Functions of cells include respiration, growth, excretion, movement, irritability and reproduction.
Published by Hodder Education © 2010 Helen McGuinness
12 Cellular respiration
Cells function through the exchange of fluids, nutrients, chemicals and ions which are carried out by passive processes such as diffusion, osmosis and filtration, and active processes such as active transport.
Cell respiration is the controlled exchange of nutrients such as oxygen and glucose and waste such as carbon dioxide by the cell to activate the energy needed for the cell to function.
Published by Hodder Education © 2010 Helen McGuinness
13 Cellular respiration
The fuel required by cells is provided by glucose from carbohydrate metabolism and oxygen absorbed from the respiratory system into the bloodstream.
Cells are bathed in a fluid known as tissue fluid or interstitial fluid which allows the interchange of substances between the cells and the blood, known as internal respiration.
Published by Hodder Education © 2010 Helen McGuinness
14 The cell’s life cycle
Cell division is the process by which cells reproduce themselves.
Mitosis is cell division that results in an increase in body cells and involves division of a nucleus.
Meiosis is reproductive cell division and results in the fusion of an egg and a sperm into a zygote.
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15 Introduction to tissues
A tissue is a group of similar cells that are specialised for a particular function.
The tissues of the body are classified into four main types: epithelial, connective, muscular and nervous.
Published by Hodder Education © 2010 Helen McGuinness
16 Epithelial tissue
Epithelial tissue provides coverings and linings of many organs and vessels.
There are two categories of epithelial tissue: simple (single layer) and compound (multi-layer).
There are four different types of simple epithelium: squamous, cuboidal, columnar and ciliated.
There are two different types of compound epithelium: stratified and transitional.
Published by Hodder Education © 2010 Helen McGuinness
17 Epithelial tissue
Type Structure Location Function
Simple squamous
A single layer of flat, scale-like cells with a central nucleus
The cells fit closely together, rather like a pavement, producing a very smooth surface
Lines the alveoli of the lungs
Lines blood and lymphatic vessels and the heart
Allows for exchange of nutrients, wastes and gases
Simple cuboidal
Single layer of cube-like cells
Ovaries, kidney tubules, thyroid gland, pancreas and salivary glands
Secretion and absorption
Simple columnar
Single layer of tall, cylindrical column cells with nucleus situated towards base of cell
Lines the small and large intestine, stomach and gall bladder
Secretion and absorption
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18 Epithelial tissue
Type Structure Location Function
Simple ciliated (columnar)
A form of columnar epithelium
Single layer of rectangular cells that contain hair-like projections (cilia) from its surface
Lines the upper part of respiratory system
Also lines the uterine tubes
The beating of the cilia carries unwanted particles along with mucus out of the system
Helps propel the ova towards the uterus
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19 Connective tissue
Connective tissue is the most abundant type of body tissue. It connects tissues and organs to give protection and support.
Connective tissue consists of the following different types: areolar, adipose, white fibrous, yellow elastic, lymphoid, blood, bone and cartilage.
Published by Hodder Education © 2010 Helen McGuinness
20 Connective tissue
Type Structure Location Function
Areolar Most widely distributed type of connective tissue in body
A loose, soft and pliable tissue containing collagen, elastin and reticular fibres
Under the skin, between muscles, supporting blood vessels and nerves and in the alimentary canal
Provides strength, elasticity, connects and supports organs
Adipose A type of areolar tissue containing fat cells (adipocytes)
Surrounds organs such as kidneys and heart
Under the skin (subcutaneous layer) between bundles of muscle fibres, in yellow bone marrow of long bones and as a padding around joints
Provides insulation, support and protection
Emergency energy reserve
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21 Connective tissue
Type Structure Location FunctionWhite fibrous
Strong, connecting tissue made up of mainly closely packed bundles of white, collagenous fibres, with very little matrix
Contains cells called fibrocytes between bundles
Forms tendons which attach muscle to bone, ligaments which tie bones together and as an outer protective covering for some organs such as the kidney and bladder
Provides strong attachment between different structures
Yellow elastic
Consists of branching yellow elastic fibres with fibrocytes in the spaces between the fibres
Arteries, trachea, bronchi and lungs
To allow stretching of various organs, followed by a return to original shape and size
Lymphoid Semi-solid matrix with fine branching fibres
Specialised cells called lymphocytes
In the lymph nodes, spleen, tonsils, adenoids, walls of the large intestine and glands in small intestine
Forms part of the lymphatic system whose function is to protect the body from infection
Published by Hodder Education © 2010 Helen McGuinness
22 Connective tissue
Type Structure Location Function
Blood Also known as liquid connective tissue, contains the blood cells erythrocytes, leucocytes and thrombocytes which float within fluid called plasma
Contained within blood vessels
Helps maintain homeostasis of the body by transporting substances throughout the body, by resisting infection and maintaining heat
Bone Hardest and most solid of all connective tissues
Tough, dense compact bones and slightly less dense cancellous bone
Bones Protects and supports other organs and soft tissues
Cartilage Much firmer tissue than other connective tissues; matrix is quite solid
See next slide on types of cartilage
See next slide on types of cartilage
Published by Hodder Education © 2010 Helen McGuinness
23 Cartilage
Type Description Location FunctionHyaline cartilage
Most abundant cartilage found in the body
Smooth, bluish-white, glossy tissue
Contains numerous cells called chondrocytes from which cartilage is produced
Found on the surfaces of the parts of bones which form joints
Forms costal cartilage which attach ribs to sternum
Forms part of the larynx, trachea and bronchi
Provides a hard-wearing low friction surface within joints
Provides flexibility in the nose and trachea
White fibrous cartilage
Tough but slightly flexible
Composed of bundles of collagenous white fibres in a solid matrix with cells scattered among them
As pads between the vertebrae called the intervertebral discs and in the symphysis pubis which joins pubis bones together
Support and to join together or fuse certain bones
Yellow elastic fibrocartilage
Yellow elastic fibres running through solid matrix, between which chondrocytes are situated
Forming the pinna (lobe of the ear) and forming the epiglottis
Provides support and maintains shape
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24 Membrane
Type Description Location Function
Mucous membrane
Lines body cavities and outer layer of organs
Lines respiratory, digestive, urinary and reproductive tracts
Lines openings to external environment and secretes viscous slippery fluid (mucus) that coats and protects underlying cells
Serous membrane
Lines body cavities not open to external environment and covers many organs
Two layers: parietal which lines the wall of body cavities and visceral which provides external covering to organs in body cavities
Pericardium of the heart
Pleural membranes in the lungs
Peritoneum lining the abdominal organs
Lines body cavities not open to external environment and secretes a thin, watery (serous) fluid that lubricates organs to reduce friction as they rub against one another and against wall of cavities
Synovial membrane
Lines joint cavities of freely movable joints
Lines spaces around certain joint cavities (shoulder, hip and knee)
Secretes synovial fluid that provides nutrition and lubrication to joints so they move without undue friction