Homeostasis & Neurophysiology Flashcards
Define physiology.
Physiology: study of biological functions, how the body works, from molecular mechanisms within cells to actions of tissues, organs and systems, and how the organism lives
State the relationship between physiology and anatomy.
-studies of physiology focuses on mechanism of action, and looking at how the body acts
-anatomy is concerned with description of structures within the body
-both combined can provide a better understanding of the human body
Define and give examples of homeostasis.
Homeostasis: dynamic consistency of the internal environment as compared to variations in the external environment
ex. maintaining body temperature, blood pressure, glucose metabolism
Discuss the relationships between the external and internal environments as they relate to homeostasis.
Homeostasis involves keeping the internal environment constant while the external environment changes.
Identify the components of a homeostatic feedback loop.
-homeostatic feedback loop involves a sensor, integrating centre, and an effector
Sensors: send information to integrating centre to allow for detection of changes from a set point
-changes then send signals from integrating centre to effector to counter deviation from set point
Discuss the relationship between the nervous and endocrine systems and their control over homeostasis.
-nervous and endocrine system extrinsically maintain homeostatic regulation
Endocrine Regulation: through chemical regulators (hormones)
-hormones can act on given organ to produce a change
Nervous System Regulation: done by innervations to target organ
-nervous system and endocrine system can interact as nervous system can control hormone release and some hormones can affect nervous system function
Discuss and give examples of negative and positive feedback loop.
-negative feedback loops maintain a state of dynamic constancy around a given set point; negative feedback loops are important for maintaining body temperature as well as blood glucose levels
-positive feedback loops aim to amplify a response; positive feedback loops are important for blood clotting as well as pre-ovulatory surge in luteinizing hormone in females
Identify the major divisions of the nervous system including: CNS, PNS, SNS, ANS, and ENS.
Central Nervous System: brain and spinal cord
Peripheral Nervous System: everything outside the CNS (nerves, ganglia, nerve plexuses)
Somatic Nervous System: division of nervous system responsible for control of skeletal muscles
Autonomic Nervous System: responsible for control of involuntary effectors such as smooth muscle, cardiac muscle and glands; further divided into sympathetic and parasympathetic nervous system
Enteric Nervous System: complex network of neurons involved in intrinsic control of GI system
Discuss the structural classification of neurons and identify anatomical features of a neuron.
-neurons contain cell body, dendrites, and axon
Cell Body: nutritional centre of neuron
Dendrites: thin, branched process that transmit signals from their ends to cell body
Axon: long process that conducts impulses away from cell body
Pseudounipolar Neurons: single, short processes that branches like a T to form a pair of longer processes
Bipolar Neurons: have 2 processes one at either end
Multipolar Neurons: have several dendrites and one axon extending from cell body
Define nucleus, ganglion, tract, somatic neuron, motor neuron, sensory neuron, afferent, efferent, and nerve as they relate to the nervous system.
Nucleus: grouping of neuron cell bodies within CNS
Ganglion: grouping of neuron cell bodies located outside CNS
Tract: grouping of axons that interconnect regions of the CNS
Somatic (Motor) Neuron: nerve that stimulates contraction of muscle
Motor Neuron: conduct impulses outside of CNS to effector organ
Sensory Neurons: conduct impulses away from sensory receptors into the CNS
Afferent: conducts nerve impulses from organ into CNS (sensory neuron)
Efferent: transmits impulses from CNS to effector organ (motor neuron)
Nerve: cable-like collection of many axons in PNS, can contain both sensory and motor fibres
Identify and briefly describe the function of speciality receptors located on dendrites.
-receptors exist on dendrites (of the postsynaptic cell) for neurotransmitters, which are released from the axon of the presynaptic cell into the synapse
-receptors allow for signals to be sent from one cell (presynaptic) to another cell (postsynaptic)
Identify the functions of the supporting cells types of the nervous system including: oligodendrocytes, Schwann cells, astrocytes, microglia, and ependymal cells.
Oligodendrocytes: responsible for myelin sheath around axons in CNS
Schwann Cells (neurolemmocytes): responsible for myelin sheath around myelinated axons in PNS
Astrocytes: cell type in CNS, covers capillaries and induces blood-brain barrier and interacts metabolically with neurons
Microglia: cell type in CNS, phagocytize pathogens and cellular debris
Ependymal Cells: cell type in CNS, forms epithelial lining of brain cavities (ventricles) and central canal of spinal cord, covers tufts of the choroid plexuses
Describe myelin and identify its role in the nervous physiology.
-myelin sheath encases axon and is formed by Schwann cells in PNS and oligodendrocytes in CNS
-myelinated axons are able to conduct nerve impulses more rapidly
Define ‘node’ and ‘anitnode’ and describe their formation.
Node: site of no myelination on a myelinated axon
Antinode: region of axon that is myelinated
-Schwann cells in the PNS and oligodendrocytes in the CNS form antinodes
Describe simple diffusion, ion channels, gating of integral membrane proteins, facilitated diffusion, primary active transport, secondary active transport, pinocytosis, exocytosis and endocytosis.
Simple Diffusion: net movement of ions or molecules from regions of higher concentration to regions of lower concentration
Ion Channels: channels in the membrane that permit the movement of ions; channels can be open or gated
Gating of Integral Membrane Proteins: gates that can open or close and channel; stimuli can open/closed channel
Facilitated Diffusion: net movement of ions from regions of high to low concentration through transmembrane protein (carrier-mediated transport)
Primary Active Transport: movement of molecules and ions against their concentration gradients where hydrolysis of ATP is the source of energy
Secondary Active Transport: movement of an ion or molecule against its concentration gradient where the energy is obtained through the movement of an ion or molecule with its concentration gradient (coupled transport)
Pinocytosis (cell drinking): invagination of the cell membrane to form narrow channels that pinch off into vacuoles; cellular intake of extracellular fluid and dissolved molecules
Exocytosis: bulk transport of large molecules out of the cell through the fusion of a membrane-bound vesicle with the plasma membrane
Endocytosis: bulk transport of large molecules into the cell through the formation of a membrane-bound vesicle from the plasma membrane
