All Flashcards
(33 cards)
Q: Hormones and Endocrine System - types
A: autocrine, paracrine, endocrine, neurocrine
Autocrine
Hormonal signal acts back on cell of origin
Paragons
Hormonal signal carried to adjacent cells over a short distance via interstitial fluid
Endocrine
Hormone signal released into bloodstream and carried to distant target cells
Neurocrine
Hormonal originates in neurone and after transport down avon released into bloodstream and carried to distant target cells
Hormones
Chemical messengers
Lipid Derived hormones
Not stored in cells, synthesised on demand from precursor lipids as lipids can diffuse through membrane
Steroid hormones formed from cholesterol
Steroid hormones transported in blood bound to serum proteins
Plants and graviperception
- Carried out by statoliths
- Shoots negatively gravitrophic
- Roots positively gravitrophic
Transfer of heat energy
Conduction
Convection
Radiation
Evaporation
Plants and thermal environment - temp regulation
Transpiration
Colours
Hairs
Waxy cuticles
leaf shape
stoma
Ectothermic Animals
Use environment to raise body temperature
Endothermic Animals
Use metabolism to raise body temperature
Four major tissues in human body
Muscle
Connective
Epithelial
Nervous
Muscle Tissue
function - movement speaking chewing
muscles types - cardiac smooth and skeletal
Fast twitch muscles
sprints, use metabolism for fuel, provides short burst of speed, fires rapidly, fatigues more quickly
Short twitch
Marathon runner, use oxygen, continuous energy, endurance
Skeletal Muscle Structure
Composed of specialised cells - myocytes
Characterised by protein filaments - actin and myosin
Neuromuscular Transmission
1- Arrival of action potential
2- Depolarisation of presynaptic membrane and opening of voltage gated Ca channels
3-Increase of intracellular Ca leads to release of Ach from synaptic vesicles
4-Binding of Ach to its receptors on ligand-gated cation channels
5- Activation of Ach gated ion channels in the end plate membrane
6-Increase of Na and K conductance via ligand gated no selective cation channels leads to generation of end plate potential
7- Generation of the EPP leads to generation of action potential of electrically excitable skeleti
muscle sarcolemma
Sliding filament model of muscle contraction
1- Rise of intracellular Ca2+
2-Binding of Ca2+ to troponin moves to tropomyosin away from myosin binding sites on actin
3- Cross bridge forms
4- Power stroke
5- Cross bridge detachment
6- Reactivation of myosin head
7- Repositioning of energized myosin head
Types of muscle contraction
Isometric - no change of muscle fibre length, tension increased
Isotonic - tension stays same, length of fibres altered
Nociception
Mechanism by which noxious peripheral stimuli are transmitted to CNS to elicit a mechanical response
Nociception and Pain
Nociception - PNS and CNS process info about external and internal environment
Pain -complex sensory and emotional experience from higher brain processing
Analgesic
Relieve pain due to single or specific pain syndromes
Opioid drugs
substance the produces morphine like effects
