Levels of Organisation Flashcards
State the levels of organisation in the body.
- organism
- systems
- organs
- tissues
- cells
- molecules
What do cells contain?
Plasma membrane and organelles
What specific range of functions do specialised types of cells perform?
- protection
- secretion
- exchange
- absorption
- communication
- movement
What are the functions of the plasma membrane?
- physical barrier + compartmentalisation
- regulation of exchange with environment
- structural support + site of attachment for proteins
- transmission of electrical + chemical signals
- secretion + uptake of substances
How do substances cross the plasma membrane?
- simple/passive diffusion
- facilitated diffusion
- exocytosis
- endocytosis
How do substances cross the plasma membrane through simple/passive diffusion?
- freely permeable (allows all substances)
- ion channels + gap junctions
(osmosis)
What is facilitated diffusion?
Passive movement of molecules across a cell via aid of a protein membrane/transporter.
- Used by molecules that can’t freely cross the phospholipid bilayer
How do substances cross the plasma membrane through facilitated diffusion?
- passive transport
- active transport (against conc gradient using energy)
- secondary active transport
How do substances cross the plasma membrane through exocytosis?
A vesicle (formed inside the cell) fuses with, and becomes part of, the plasma membrane.
- vesicle contents then released into the extracellular environment
How do substances cross the plasma membrane through endocytosis?
Basically engulfing molecules, 3 main types:
- phagocytosis (large molecules)
- pinocytosis (small molecules)
- receptor-mediated endocytosis (specific form of pinocytosis)
What are the 4 classes of tissue?
- epithelial
- connective
- nervous
- muscular
Describe epithelial tissue
- simple epithelia: squamos, cuboidal, columnar, pseudostratified
- stratified epithelia
Describe the types of connective tissues
- connective tissue proper: includes both loose + dense
- fluid connective tissue: blood, lymph
- supporting connective tissue: bone, cartilage, adipose tissue
Describe nervous tissue
- neurones: consist of cell body, dendrites + axon
- glial cells: schwann cells
What are the types of muscular tissue?
- skeletal
- cardiac
- smooth
