6.4 Tissues Flashcards
What is the definition of ‘tissue’?
A collection of differentiated cells that have a specialised function/functions in an organism
What are the 4 main types of tissues? How is each one adapted?
- Nervous tissue - Supports transmission of electrical impulses
- Epithelial tissue - Adapted to cover body surfaces, internal and external
- Muscle tissue - Adapted to contract
- Connective tissue - Adapted to either hold tissues together or act a transport medium
What is the squamous epithelium made up of? What is the squamous epithelium also known as? Why is it called this?
Squamous epithelial cells
Sometimes known as ‘pavement epithelium’ due to its flat appearance
Explain the characteristics of the squamous epithelium?
Very thin - Due to flat cells that make it up + bc it’s one cell thick
When is the squamous epithelium used?
When rapid diffusion across a surface is necessary
Where can squamous epithelium be found? Why is this an adaptation?
Forms the lining of lungs - allows rapid diffusion of oxygen into the blood
What is the ciliated epithelium made up of?
Ciliated epithelial cells
What are cilia?
Hair-like structures on one surface of ciliated epithelial cells that move in a rhythmic manner
Where can the ciliated epithelium be found? Why is this an adaptation?
On the lining of the trachea - causes mucus to be moved away from the lungs
Where are goblet cells found?
Inside ciliated epithelium
What is the function of goblet cells? Why is this a benefit?
Release mucus to trap any unwanted particles present in the air.
The benefit of this is that any particles e.g. bacteria are prevented from reaching the alveoli inside lungs
What type of tissue is cartilage?
Connective tissue
Where is cartilage found?
Outer ear, nose and at the end of and between bones
What does cartilage contain?
Fibres of the proteins elastin and collagen
Describe the structure of cartilage?
Cartilage is a firm, flexible connective tissue composed of chondrocyte cells embedded in an extracellular matrix
What is the function of cartilage?
Prevents ends of bones rubbing together and causing damage
What organism has the majority of its skeleton composed of cartilage?
Fish
What ability does muscle need and why does muscle need this ability?
Muscles need to be able to shorten (contract) to move bones, which move other parts of the body
What are skeletal muscle fibres?
Muscles which attach to the bone
What do skeletal muscle fibres contain?
Myofibrils which contain contractile proteins
What are 2 types of plant tissues and what are they adapted for?
Epidermis tissue - cover plant surfaces
Vascular tissue - Transport water and nutrients
What is the epidermis?
Single layer of closely packed cells covering surfaces of plants
What is the epidermis covered in to prevent water loss?
Waxy, waterproof cuticle
Where are stomata found?
Inside the epidermis
What is the function of stomata?
Allow CO2, water vapour and oxygen in and out of the cell
What type of tissue is the xylem composed of?
Vascular
What is the function of the xylem?
Transport water and minerals throughout the plant
What is the xylem composed of?
Vessel elements, which are elongated dead cells
What do the walls of vessel elements contain?
Lignin - Waterproof + strengthens the cells, providing structural support for plants
What type of tissue is the phloem composed of?
Vascular tissue
What is the role of the phloem?
Transport organic nutrients, mainly sucrose, from leaves and stems to all parts of the plant where its needed
What is the phloem composed of?
Columns of sieve tube cells separated by perforated walls called sieve plates
