Animal Tissues Flashcards
What are the four main type of tissues in the body
Epithelial
Connective tissues
Muscle tissues
Nervous tissues
Define tissues
Group of cells that work together to perform specific function/set of functions
Epithelial tissues uses and examples
Covers and lines free surfaces in the body
Such as -skin
Cavities of the respiratory and digestive systems
Blood vessels
Heart chambers and walls of organs
What are the characteristics of epithelial tissues
- made up almost entirely of cells
- cells are very close and form continuous sheets.
- Adjacent cells are bound together by lateral contacts , such as tight junctions and desmosomes
- no blood vessels, cells receive nutrients by diffusion by tissue fluid in the underlying connective tissue
- some have smooth surfaces, some have projections -cilia or microvilli
- have short cycles- divide up to two or three times a day to replace worn/damaged tissue
What is epithelial tissue specialised for?
Carrying out its function of protection , absorption, filtration , excretion and secretion
Connective tissue
Consists of non-living extra cellular matrix containing proteins (collagen and elastin )
And polysaccharides (such as hyaluronic acid which traps water
The matrix separates in living cells within tissue and enables it to withstand forces such as weight
Give six examples of connective tissue
Blood Bone Cartilage Tendons Skin Ligaments
What are chondroblasts
Immature cells in cartilage
Explain how chondroblasts turn into Chondrichthyes
They can divide by mitosis and secrete the extra cellular matrix.
Once the matrix has been synthesised the chondroblasts become mature, less active Chondrichthyes , which maintain the matrix
What are the three main type of cartilage
-hyaline
Fibrous
-elastic
Hyaline cartilage
-form the embryonic skeleton , covers the ends of long bones in adults joins ribs to sternum and is found in the nose, trachea and larynx
Fibrous cartilage
Occurs in the discs between the vertebrae in the backbone and knee joint
Elastic cartilage
Makes up the outer ear (pinna)
And the epiglottis (flap that covers over the larynx when you swallow)
Muscle tissues
Well vascularised
Called fibres-
They are elongated and contain special organelles called myofillaments , these allow muscles to contract
Functions of muscle
- allow movement
- skeletal muscle ; packaged by connective tissue sheets, joined to bones by tendons :these muscles hen they contract cause bone to move
- cardiac muscle; makes up the walls of the heart and allows the heart to beat and to pump blood
- smooth muscle ; occurs in the walls of intestine, blood vessels , uterus and urinary tracts, and it propels substances along this tract
Epidermal cells
Consists of flattened cells, which lack chloroplasts and form a protective covering over leaves, stems and roots.
Some epidermal cells also have walls impregnated with waxy substance , forming a cuticle.
Why are epidermal tissues important to plants that live in dry places?
As the cuticle reduces water loss
Vascular tissue
Concerned with transport
What are the two types of vascular tissue
Xylem and Phloem
What is xylem role
Carry water and minerals from roots to all parts of the plant
Phloem vessels role
Sieve tube transfer the products of photosynthesis (mainly from sucrose sugar), in solution, from leaves to parts of the plant that do not photosynthesise , such as roots, flowers, growing shoots
What type of cells are contained in meristematic tissue
Stem cells
Why are meristematic tissue important
It is from this tissue that all other plant tissue are derived by cell differentiation
Where are m tissues found
Roots and shoot tips
In the cambium of vascular bundles
The cells in meristems
- have thin walls containing little cellulose
- don’t have chloroplasts
- don’t have large vacuole
- can divide by mitosis
Why do mature plants develop a large vacoules and cellulose cell wall?
These prevent the cells from dividing
How are xylems derived from meristems
- lignin is deposited in their cell walls to reinforce and waterproof them :however this also kills cells
- the ends of the cells break down so that xylems forms continuous columns with wide lumens to carry water and dissolved minerals
Phloem sieves from meristems
Sieve tubes lost most of their organelles, and sieve plates develop between them
Companion cells from meristems
Companion cells retain their organelles and continue metabolic functions to provide ATP for active loading of sugars into the sieve tubes
List al the plant organs
Leaf
Root
Stem
Flower
Leafs function as a plant organ
-photosynthesis
Roots function as a plant organ
- anchorage in soil
- absorption of mineral ions and water
- storage ,e.g carrot roots store carbohydrates
Stems function as plant organs
- support
- holds up leaves for more sun exposure
- transportation of water and minerals
- transportation of photosynthesis products
- storage of products of photosynthesis
Flowers unctions as plant organs
-sexual reproduction
Organ definition
A collection of tissues working together to perform the same function is called an organ
Tissue definition
Group of cels that work together to perform a specific set of functions
