Topic 9

• What is an endotherm?


  warm-blooded organism
• What is an ectotherm?

  a cold-blooded animal
• where are exocrine glands secreted from?


  ducts
• where are endocrine glands scecreted?

  bloodstream
• which hormones does the posterior pituitary gland relase?

  oxytocin and ADH
• which hormones fros the anterior pituitary gland release?

  ACTH, LH, FSH, TSH, prolactin, growth hormone,
• what does oxytocin cause?


  muscle contractions in uterus
• what does ADH effect?

  permeability of kidney tubules
• FSH is the production of?

  oestrogen and sperm
• LH is used in?

  ovulation and testosterone production
• what does prolactin cause?

  milk production from mammary glands
• is adrenaline a hydrophobic or hydrophillic hormone?

  Hydrophobic
• is oestrogen a hydrophilic or hydrophobic hormone?

  Hydrophilic
• a seed absorbs water, which causes gibberellin to be produced in the embryo. this synthesises amylase, which breaks down starch (in the endosperm) into maltose. this turns into glucose, which is used in the embryo.
• auxins bind to cells and cause ph to decrease. this loosens cell wall, so water enters cell, elongating it.
• Pr is converted to Pfr when?

  daylight
• Pfr is converted to Pr when?

  night
• in long day plants, does Pfr inhibit or promote flowering?

  promote
• in short day plants, does Pfr inhibit or promote flowering?

  inhibit
• hormones are produced in the neurosecreatory cells 2, then transported to the posterior pituitary gland once a stimulus has happened.
• releasing factors and release-inhibiting factors are released into the portal vessels/anterior pituitary gland, from neurosecretory glands 1 which will then cause other glands to produce hormones.
• stimulus —— receptor —— sensory neurone —— relay neurone and CNS —— motor neurone —— effector
• In motor and sensory neurone, impulse moves from dendrites to synaptic bulbs. Effector is at the synaptic bulb in motor, receptor is at dendrites in sensory
• node of ranvier are the gaps between Schwann cells around the axon
• threshold potential is the minimum amount of stimulation needed to trigger an action potential in a neuron (-50mV)
• during depolarization, voltage gated Na+ channels open and Na+ moves into the cell
• during polarization, the voltage gate K+ channels open and K+ moves out of cell
• during the refractory period, the levels of Na+ and K+ need to return to normal, so leak K+ channels and na+/k+ pumps are used to restore the resting potential
• Steps of synaptic transmission

  • depolarization causes voltage gated calcium channel to open
  • causes vesicles with NT to move to membrane
  • NT diffuse across synaptic cleft, binds with post-synaptic receptors
  • Sodium channels open, na enters causing depolarization (action potential)
  • enzymes break down NT in cleft, active transport back in to pre-synaptic neurone
• Where does acetate come from in actylcholine?

  AcetylCoA
• what is actylcholine?

  neurotransmitter
• where is noradrenaline found?

  sympathetic nervous system
• where is actylcholine found?

  parasympathetic nervous system
• lidocaine blocks voltage gated sodium channels, prevents depolarization so there is no action potential in sensory neurones.

  it can also prevent arrhythmias by reducing action potential in pacemaker reigon
• cobra venom binds irreversibly to actylcholine receptors on post-synaptic neurone. prevents transmission of impulse across synapses, muscles can’t contract, causing paralysis. it can then cause death if breathing muscle is paralysed
• how many bipolar cells do cone cells synapse with?

  1
• how many bipolar cells do rod cells synapse with?

  Multiple
• which cells are mainly in your peripheral vision?

  rods
• which cells are on your fovea?

  cones
• rod cells are used in low light intensity and have low resolution - because multiple rods synapse with a biopolar cell, so the brain doesn’t know which rod the action potential is coming from, so blurry.