2.1.6 Cell cycle - Tissues, organs and organ systems

Question 1

Define Tissue

Answer 1

A tissue is made up of a collection of differentiated cells that have a specialised function or functions.

Question 2

What are the four main categories of tissues in animals?

Answer 2

Four main categories of tissues in animals:

• Nervous tissue, adapted to support the transmission of electrical impulses
• Epithelial tissue, adapted to cover body surfaces, internal and external
• Muscle tissue, adapted to contract
• Connective tissue, adapted either to hold other tissues together or as a transport medium.

Question 3

How are Squamous epithelium specialised?

Answer 3

Very thin (due to the squat or flat cells that make it up) and only one cell thick which allows for rapid diffusion across a surface e.g. in the lining of the lungs (alveoli)

Question 4

Where are Squamous epithelium found?

Answer 4

The lining of the lungs (alveoli).

Question 5

How are ciliated epithelium specialised?

Answer 5

Cilia on the surface (that move in a rhythmic manner) causes mucus to be swept away from the lungs.
Goblet cells are present which releases mucus to trap any unwanted particles present in the air.

Question 6

Where are ciliated epithelium found?

Answer 6

The lining of the trachea

Question 7

Cartilage -

Answer 7

• Connective tissue
• Found in the outer ear, nose, and at the ends of (and between) bones.
• Contains fibres of the protein’s elastin and collagen.
• Cartilage is a firm, flexible connective tissue composed of chondrocyte cells embedded in an extracellular matrix.
• Cartilage prevents the ends of bones from rubbing together and causing damage.

Question 8

Muscle -

Answer 8

• Muscle is a tissue that needs to be able to shorten in length (i.e. contract) in order to move bones, which in turn moves the different parts of the body.
• Many different types of muscle fibres.
• Skeletal muscle fibres (muscles which are attached to bone) contain myofibrils which contain contractile proteins.

Question 9

What are the different tissues in plants?

Answer 9

There are a number of different tissues in plants, including:

• Epidermis tissue, adapted to cover plant surfaces
• Vascular tissue, adapted for transport of water and nutrients

Question 10

Epidermis -

Answer 10

• Single layer of closely packed cells covering the surfaces of plants.
• Usually covered by a waxy, waterproof cuticle to reduce the loss of water.

Question 11

Xylem tissue -

Answer 11

• Type of vascular tissue
• Responsible for transport of water and minerals throughout plants.
• Tissue is composed of vessel elements, which are elongated dead cells.
• The walls of these cells are strengthened with a waterproof material called lignin, which provides structural support for plants.

Question 12

Phloem tissue -

Answer 12

• Type of vascular tissue in plants
• Responsible for the transport of organic nutrients, particularly sucrose, from leaves and stems where it is made by photosynthesis to all parts of the plant where it is needed.
• Composed of columns of sieve tube cells separated by perforated walls called sieve plates.

Question 13

Define Organ

Answer 13

An organ is a collection of tissues that are adapted to perform a particular function in an organism.

Question 14

Define Organ System

Answer 14

Each organ system is composed of a number of organs working together to carry out a major function in the body.
Large multicellular organisms have coordinated organ systems.