Specialised Cells, Tissues and Organs
Erythrocytes (Red blood Cells) - Animal
*Flattened biconcave shape* increase SA for Oxygen exchange *No* nuclei or other organelles (in mammals) to increase space for haemoglobin *Flexible* to fit through narrow capillaries 7.5 micrometer diameter, 2micrometer height
Muscle tissue
Adapted to *contract*
Epithelial tissue
Adapted to cover body surfaces, internal *and* external
Connective tissue
Adapted to hold tissue *together* or as a *transport medium*
Nervous tissue
Adapted to support the transmission of electrical impulses
Gaseous exchange system - Animal organ system
Brings air into the body O2 can be extracted for respiration CO2 can be expelled
Organs
Collection of *tissues* that are adapted to perform a particular function within an organism
Tissue
Collection of differentiated cells that have a specialised function/s Each tissue is *adapted* for a particular function within the organism There are *4* main types of tissue in animals: Nervous, epithelial, muscle, connective
Cartilage - Animal tissue
Connective tissue (outer ear, nose, at the end and between bones) Contains *collagen* and *elastin* fibres Firm, flexible connective tissue composed of *chondrocyte* cells embedded in *extracellular matrix* Prevent bone ends rubbing together and causing damage Fish have complete cartilage skeletons
Muscle - animal tissue
Contracts and relaxes in order to move bones Skeletal muscle fibres contain *myofibrils* that contain *contractile proteins* Each pink strip is a muscle fibre, each white strip is connective tissue
Guard Cells - Plant
Form stomata Control gasses entering/leaving the cell (CO2 enter for photosynthesis) Thick inner wall means a change in osmotic forces causes the stomata to open or close was water comes in or leaves When there is a low water supply, osmotic pressure's low so the stomata closes, conserving water
Organ systems
Large multicellular organisms have *coordinated* organ systems each organ system is composed of a number of *organs* working together to carry out a major bodily function
Ciliated Epithelium - Animal tissue
Made up of ciliated epithelial cells Cells have *hair-like* structures (cilia) on one surface that move in a *rhythmic* manner It lines the trachea, sweeping mucus away from the lungs Goblet cells also present, secreting mucus, trapping unwanted particles, preventing bacteria reaching the lungs
Squamous Epithelium - Animal tissue
Made up of squamous epithelial cells (sometimes known as *pavement* epithelium) Very *thin*, one cel thick, flat cells Present when rapid diffusion *essential* Forms lining of lungs to allow rapid diffusion of oxygen into blood
Sperm cells - Animal
Male *gametes* Delivers male genetic information to *ovum* (egg) Long flagellum for movement (40 micrometers) requires many *mitochondria* *Acrosome* contains digestive enzymes , released to digest protective layers of ovum, leading to fertilisation
Cardiovascular system - Animal organ system
Moves blood around the body to provide an effective transport system for the substances it carries
Neutrophils (type of white blood cell) - Animal
Plays important part in *immune system* *Multi-lobed nucleus* makes it easier to squeeze through small gaps to infection sites *Granular* cytoplasm contains many *lysosomes* containing enzymes used to attack infectious pathogens 10-14 micrometer diameter
Root hair cells - Plant
Present at surfaces of root near growing tips Long root hairs increase SA of the cell Maximises uptake of water and minerals from the soil
Palisade Cells - Plant
Present in *mesophyll* Contain *chloroplasts* to absorb light for *photosynthesis* Rectangular box shape lets cells be stacked tightly together in a continuous layer Thin cell walls reduce diffusion distance Large vacuole maintains *turgor* Chloroplasts can move about to absorb more light
Epidermis - Plant tissue
Single layer of closely packed cells covering plant surfaces Usually covered by waxy, waterproof cuticle to reduce water loss Stomata are present, controlled by guard cells, that control of gaseous exchange
Digestive system - Animal organ system
Takes in food Breaks down large insoluble molecules into small, soluble ones Absorbs nutrients into the blood retains water needed by the body and removes any undigested material from the body
Specialised cells
The cells within a multicellular organism are *differentiated* - specialised to carry out particular functions
Phloem - Plant tissue
Vascular tissue responsible for the transport of organic nutrients (particularly *sucrose*) from leaves and stems (made by photosynthesis) to all parts of the plant where it is needed Composed of sieve tube cells separated by perforated walls called *sieve* plates
Xylem - Plant tissue
Vascular tissue responsible for transport of water and minerals throughout plants Composed of *vessel elements* (elongated, dead cells) Walls strengthened by *lignin* which provides structural support for plants