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HL 2 Biology

E.4b Neurotransmitters & Personality

<<Transmitters and Synapses>> Synaptic Transmission action potential in pre-synaptic neuron release of neurotransmitter (to synaptic cleft) neurotransmitter binds to receptors in membrane action potential stimulated in post-synaptic neuron Synapses more than one pre=synaptic neuron = able to form synapse with same post-synaptic neuron often a single release of NT from 1 pre-synaptic neuron = insufficient … Continue reading

HL 2 Biology

E.4a Neurotransmitter & Synapses

AA-CC: 331-2 • AA-SG: 138 Lesion Studies and Animal Experimentation lesion: area in organ/tissue that suffered damage due to injury/disease (e.g. tumor) changes personality and capacity for social interactions e.g. Phineas Gage; damage to frontal lobes in his brain; personality changed lesion experiments practiced on animals (vivisection) remove parts of the skull, experiment on parts … Continue reading

HL 2 Biology

E.5b Brain Function

<<Sympathetic & parasympathetic control>> Peripheral nervous system: all nerves outside central nervous system two parts: voluntary and autonomic nervous system autonomic: control unconscious processes; this further divides to sympathetic and parasympathetic systems parasympathetic nerves: cause increase in blood flow to gut wall hen guts active sympathetic nerve: cause decrease in blood flow during fasting/when blood needed elsewhere (e.g. muscles when exercising intensely ) heart rate – … Continue reading

HL 2 Biology

E.5a Brain Structure

The Human Brain.. medulla oblongata:  automatic & homeostatic activities e.g. breathing, vomiting cerebellum: unconscious activities e.g. posture, balance hypothalamus: maintains homeostasis (nervous & endocrine system) secretes hormones stimulates appetite/thirst, body temp, and sleep pituitary gland: releases hormones release hypothalamic hormones cerebral hemispheres: integrates complex functions e.g. memory, emotion, language many cases of injury here cause difficulty … Continue reading

HL 2 Biology

E.2c Ears

How sound is perceived: eardrum vibrated by sound waves transmits mechanical vibration of air molecules –> middle ear bones of middle ear ossicles = series of very small bones 1st = attached to eardrum 3rd = attached to oval window muscles = attached to ossicles (protect from loud sound) acts as lever to amplify sound … Continue reading

HL 2 Biology

E.2a Perception of Stimuli

p. 323-4 <<Perception of Stimuli>> stimuli: detected by receptors some located in sense organ, nerve endings of sensory neurons Humans have: mechanoreceptors, chemoreceptors, thermoreceptors and photoreceptors. mechanoreceptor perceive movements e.g. in the ear = perceive sound vibrations. movements due to gravity in the skin = perceive pressure changes chemoreceptors perceive chemical substances (taste and smell) membrane receptor … Continue reading