2.1.6 Differentiation and Organisation
Organisation into Tissues
Epithelial tissue
Connective tissue - cartilage
Muscle tissue
Vascular tissue
Meristematic Tissue
Organisation into Systems
Plant Organs
Animal Organs
Digestive system
Circulatory system
Respiratory system
Urinary system
Integumentary system
Skeletal system
Immune system
Nervous system
Endocrine system
Reproductive system
Lymph system
Stem Cells
Differentiation: process by which stem cells become specialised into different types of cells e.g. change shape, contents, organelles of cell
Potential Uses
repair of damaged tissues; develop into liver cells to treat liver disease; develop into pancreatic beta cells to treat diabetes; regenerative medicine to produce a bioscaffold of organ and use patients own cells to make organ so immunosuppressants are not needed
treatment of neurological conditions e.g. Alzheimer's and Parkinson's; develop into nerve tissue and also repair spinal injuries
research into developmental biology; study how cells develop and differentiate; see cell functions; growth and repair in later life
Found
embryonic stem cells; present when zygote begins to divide;
umbilical cord blood stem cells
adult stem cells; found in bone marrow, blood, brain, muscle; act as repair system
induced pluripotent stem cells (iPS cells); developed in labs by reprogramming differentiated cells and switching on and off certain key genes
Bone marrow transplants; treat diseases of blood e.g. leukemia, sickle cell anemia; used to restore patients blood system after cancer treatment
drug research; stem cells develop into human cells that form a tissue that drugs can be tested on, before humans
transport fluids back to the circulatory system; resisting infection e.g. lymph nodes, lymph vessels
communication, control, coordination; e.g. hormone glands; thyroid, ovaries, testes, adrenals
protection against pathogens e.g. bone marrow, skin, stomach acid, blood
waterproofing, protection, temperature regulation e.g. skin, hair, nails
breathing and gas exchange; excretion e.g. lungs, airways, diaphragm
nutrition to provide ATP for growth and repair e.g. oesophagus, stomach, intestines, liver, pancreas
excretion; osmoregulation e.g. kidneys, ureters, bladder
support; protection; movement e.g. skeleton, skeletal muscles
communication, control, coordination e.g. brain, spinal cord, nerves
reproduction e.g. testes, penis, ovaries, uterus, vagina
e.g. heart, lungs, liver, kidneys, brain, muscles, eyes
leaf; photosynthesis
root; anchorage, absorption of mineral ions and water, storage
stem; support, holding leaf up, transport water and minerals and sugars, storage
flower; sexual reproduction
transport to and from cells e.g. heart, blood vessels
made up almost entirely of cells packed together tightly to form continuous sheets
contain no blood vessels; obtain nutrients via diffusion from tissue fluid
ciliated of squamous cells
short cell cycle to replace worn or damaged tissue
protection, absorption, filtration, excretion, secretion
non-living extracellular matrix made of proteins (collage, elastin) and polysaccharides (hyaluronic acid) to separate living cells to withstande forces
e.g. blood, bone, cartilage, tendons, ligaments. skin
hyaline cartilage; forms embryonic skeleton, covers ends of long bones, nose, trachea
fibrous cartilage; disks between vertebrae in backbone, and knee joint
elastic cartilage; outer ear and epiglottis
well vascularised; has many blood vessels
elongated muscle fibres; contain myofilaments made of actin and myosin; allow muscle fibres to contract
skeletal muscle; packaged by connective tissue sheet, joined to bones by tendons; when contract, allow bones to move
cardiac muscle; walls of heart; allows heart to pump blood
smooth muscle; walls of intestine, blood vessels, uterus, urinary tract; propels substances along these tracts
xylem carry water and minerals from roots to other parts of plant
phloem sieve tubes transport sugars around the plant
contain stem cell; found at roots and shoot tips and cambium of vascular bundles
meristem cells; thin walls with little cellulose; no chloroplasts; small vacuole; divide by mitosis and differentiate
cambium cells differentiate into xylem;: lignin deposited in cells to kill cells, waterproof them and reinforce them; ends of cells break down so xylem forms continuous columns with wide lumens to carry water and dissolved minerals
cambium cells differentiate into phloem; sieve tubes lose organelles and sieve plates develop between them; companion cells retain organelles and continue metabolic functions to provide ATP for active loading of sucrose
Sammer Sheikh