5.3 - Neural Communication Flashcards
What is a sensory receptor?
Specialised cell that detects change in an environment. An energy transducer that converts energy from one form to another, e.g. light energy into biochemical energy of the action potential.
Name stimuli, their receptor and the energy change.
Stimulus: Light intensity. Receptor: Rods and cones in eye. Energy change: Light to electrical.
Stimulus: Temperature. Receptor: Skin receptors and hypothalamus. Energy change: Heat to electrical.
Stimulus: Pressure. Receptor: Pancinian corpuscles in skin. Energy change: Movement to electrical.
Stimulus: Sound. Receptor: Vibration receptors in cochlea. Energy change: Movement to electrical.
Stimulus: Muscle length. Receptor: Spindle fibres. Energy change: Movement to electrical.
Stimulus: Chemicals in air. Receptor: Olfactory cells in nose. Energy change: Chemical to electrical.
Stimulus: Chemicals in food. Receptor: Receptors in taste buds. Energy change: Chemical to electrical.
What is the Pacinian corpuscle?
Pressure sensor in skin.
Describe the structure of the Pacinian corpuscle.
Oval shaped, concentric rings of connective tissue.
Wrapped around nerve ending.
Pressure distorts rings of connective tissue.
Sensitive only to changes in pressure.
If pressure is constant, cells stop responding.
Name the proteins associated with the nervous system and describe their action.
Protein: Sodium ion channels. Action: Ion specific channels, sensitive to small movements in nerve membrane, distortion increases permeability of membrane to sodium ions allowing diffusion into cell, may be gated.
Protein: Potassium ion channels. Action: Ion specific channels, may be gated.
Protein: Sodium/ potassium pump. Action: Active transport of 3 sodium ions out of nerve cell; active transport of 2 potassium ions into nerve cell.
Describe the nerve cell membrane when at rest.
Polarised. More positive sodium ions leave the membrane then positive potassium ions enter. Negatively charged on inside compared to outside.
