Anatomy and Physiology Answer Key

B hormones bring about a metabolic change and often

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Unformatted text preview: non-compressible, the pressure wave moves the membranes in the cochlea, causing the hair cells to be stimulated. Skin Senses (page 90) 1. Forearm. 3. (a) Endocrine signalling, where a hormone is carried in the blood between the endocrine gland/ organ where it is produced to target cells. (b) Paracrine signalling, where cell signalling molecules are released to act on target cells in the immediate vicinity, e.g. at synapses or between cells during development. (c) Autocrine signalling, where cells produce and react to their own signals (e.g. growth factors from T cells stimulate the production of more T cells). 2. The three signalling types all have in common some kind of chemical messenger or signal molecule (ligand) and a receptor molecule (on the target cells, which may or may not be on the cell producing the signal). Lips and/or fingertips. 2. 1. The lips and/or fingertips need to be sensitive to carry out their functions (locating and tasting food, communication etc,). They therefore need to have a great number of receptors. The forearm requires many fewer as it is not involved in intricate tasks. Taste and Smell (page 91) 1. Chemical sense relies on the chemicals (scent molecules) binding to membrane-bound sensory receptors and inducing a change in membrane potential in the sensory cell (signal transduction). These electrochemical messages are relayed to the appropriate centers in the brain where they are interpreted. 2. Example only: 10 s: 1 (very strong) 20 s: 2 (quite strong) 30 s: 3 (noticeable) 40 s: 4 (weak) 50 s: 5 (very faint) 60 s: 6 (could not detect) 3. (a) The sense of smell (to that scent) declines. (b) Sensory adaptation. The sensory cells adapt to the stimulus and cease responding to it. (c) It is adaptive to stop responding to stimuli that are constantly present and do not change in intensity. Appropriate responses are directed to new stimuli. Hormonal Regulatory Systems (page 93) 1. (a) Antagonistic hormones: Two hormones that have contrasting (counteracting) effects on Biozone International 2009 Photocopyin...
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This document was uploaded on 01/28/2014.

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