Chapter 6 Physiology PDF

**[Chapter 6]** 1. Describe three forms of local communication and two forms of long-distance communication. **The distinction between local and long-distance is a concept people seem to be forgetting as the semester goes on.** - **Local Communication**: 1. **Gap Junctions**:...

**[Chapter 6]** 1. Describe three forms of local communication and two forms of long-distance communication. **The distinction between local and long-distance is a concept people seem to be forgetting as the semester goes on.** - **Local Communication**: 1. **Gap Junctions**: Direct cytoplasmic connections between adjacent cells that allow ions and small molecules to pass (e.g., cardiac muscle cells). 2. **Contact dependent signals:** require cell-to-cell contact; cell adhesion molecules (CAMs) 3. **Diffusing chemicals:** - Paracrine Signaling: Chemical signals released by a cell affect nearby cells (e.g., histamine during inflammation). - Autocrine Signaling: A cell releases a chemical that acts on itself (e.g., immune cells releasing interleukins). - **Long-Distance Communication**: 4. **Blood Transport** - **Endocrine System**: Hormones released into the bloodstream act on distant targets (e.g., insulin regulating glucose levels). 5. **Neurochemicals** - Neurotransmitters: released by neuron into synaptic cleft - Neuromodulators: modulate other neurons - Neurohormones: neuron releases hormone into blood A diagram of cell division Description automatically generated  2. Explain the general sequence of events that follow lipophilic ligand binding to intracellular receptors. Slower response related to changes in gene activity 3. Describe the general sequence of events that follow lipophobic ligand binding to a cell surface receptor. Rapid cellular response A diagram of cell neurons Description automatically generated 4. Name and describe four major groups of cell surface receptors. 5. Apply the concepts of specificity, competition, affinity, and saturation to receptors and their ligands. Note: receptor type depends on location - **Alpha receptors**: bind epi; found in intestinal blood vessels and cause vasoconstriction - **Beta receptors**: bind epi; found in skeletal muscle of blood vessels and cause vasodilation 6. List the seven steps of a reflex control pathway in the order in which they occur. 7. Compare the speed, specificity, types of signals, and duration of action in neural and endocrine reflexes. How is stimulus intensity coded in each type of reflex? - **Neural Reflexes**: - **Speed**: Very fast (milliseconds). - **Specificity**: Highly specific; targets specific cells. - **Signals**: Electrical (along neurons) and chemical (neurotransmitters). - **Duration**: Short-lived. - **Stimulus Intensity Coding**: Frequency of action potentials (increased) - **Endocrine Reflexes**: - **Speed**: Slower (minutes to hours). - **Specificity**: Broad; hormones affect all cells with appropriate receptors. - **Signals**: Chemical (hormones in the bloodstream). - **Duration**: Longer-lasting. - **Stimulus Intensity Coding**: Hormone concentration (increased) NOTE: these are mediated by the nervous system OR endocrine, NOT both; neuroendocrine is complex and is mediated by both  A screenshot of a medical report Description automatically generated