Practice Flashcards
Cells derived from fusion of monocytes that release enzymes for breakdown of bone
Osteoclasts (clasts = Kill)
Mature bone cells that maintain daily bone metabolism
Osteocyte
Trabeculae
Lattice work of thin plates of bone
Four primary tissue types are
connective, epithelial, skin and blood
Muscle around the mouth
orbicularis Oris
Forehead Muscle
Occipitofrontalis
Chest muscle
pectoralis major
Forearm muscle
supinator
Muscle centre of Quad
Rectus femoris
Muscle next to tibia
soleus
main hamstring muscle
Bicep femoris
calf muscle
gastrocnemius
Interphase
G1- cells grow larger, copies organelles
S Phase - synthesises complete copy of DNA, duplicates centrosome
G2 - Cell continues to grow, makes proteins and organelles
Early prophase
- Chromosomes start to condense
- mitotic spindle begins to form
- nucleolus disappears
Late prophase
- Nuclear envelope breaks down
- Chromosomes fully condensed
- Mitotic spindle continues to grow and starts to capture chromosomes
Metaphase
Spindle has captured all chromosomes and lined them up on the metaphase plate ready to divide
Anaphase
The sister chromatids seperate from each other, each now their own chromosome
They are pulled towards opposite ends of the elongated cell
Telophase
Mitotic spindle is broken down
2 new nuclei form, one for each set of chromosomes
Nuclear membrane reappears
Chromosomes de-condense
Cytokinesis begins
Cytokinesis
Division of cytoplasm to form two new cells
It is a contractile band of filaments made of protein actin that pinches the cell
The pinch crease is known as cleavage furrow
When complete 2 new daughter cells are formed with a complete set of chromosomes
Cell junctions
Tight junction
Gap junction
Desmosomes
Tight junction
forms watertight cell and prevents liquid escaping between cells
Gap junctions
they are channels between neighbouring cells that allow for the transport of ions, water, and other substances
Desmosomes
anchoring junction, pin adjacents cells together
Bone growth in length
The epiphyseal plate is the site of bone growth. Cartilage cells are produced by mitosis on the epiphysis side of the plate. Cartilage cells are destroyed and replaced by bone on diaphyseal side of the plate. This produces growth in length. Epiphyseal plates close at ages 18-25 therefore cartilage cells stop dividing and bone replaces the cartilage producing the epiphyseal line
Describe muscle contraction cycle
Myosin heads hydrolyse ATP and become reorientated and energised
Myosin heads bind to actin forming crossbridges
Myosin crossbridges rotate toward centre of the sarcomere (contraction)
As myosin heads bind ATP, the crossbridges detach from actin
Neuroglia Phagocyte like cell
Microgila
Form myelin sheath around axons
Oligodendrocyte
Astrocytes
form Blood brain barrier, metabolise neurotransmitters
Conducts nerve impulses towards the cell body
dendrites
Axons
conduct nerve impulses away from cell body
Neuron communication - graded potentials
local membrane changes only
Neuron communication - action potential
Travel long distances, widespread distance in change
Ganglia
Collection of nerve cell bodies found outside the CNS
All or none principle
when stimulus reaches a threshold, action potential is always the same ( a stronger stimulus will not cause a larger impulse
During this period a second action potential can only be initiated by a larger than normal stimulus
Relative refractory period
Absolute refractory period
very strong stimulus will not begin another action potential
Endorphins belong to
Neuropeptide neurotransmitter class
elevated ridges on the surface of cerebal cortex are called
the gyri - these occur between the sulci
Determine stretch or tension in tendons
Golgi organs
otholitic organs (inner ear) are sense organs for
static equilibrium
Fight or flight response is the role of
Sympathetic nervous system
located on the trachea and Releases hormonones involved in metabolism and calcium blood level regulation
thyroid gland
which gland is classified as an endocrine and exocrine gland
pancreas
