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130 Cards in this Set
- Front
- Back
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Physiology
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study of how body works to maintain life
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Phase I
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healthy human volunteers
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Phase II
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target population
Effective? Toxic? |
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Phase III
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diverse target population
Effective? Toxic? Contraindicated? |
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Phase IV
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Other potential uses?
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Homeostasis
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is the property of a system, either open or closed, that regulates its internal environment so as to maintain a stable, constant condition.
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Dynamic constancy
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Set point
By negative feedback loops |
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Negative Feedback Loops
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Sensor: Detects deviation from set point
Integrating center: Determines response Effector: Produces response |
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Positive feedback
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amplifies changes
Ex- producing blood clots Ex- contractions and oxytocin secretion in labor |
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The Primary Tissues
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includes muscle, nervous, epithelial and connective tissues
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Muscle Tissue
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3 types: skeletal, cardiac, smooth
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Skeletal Muscle
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Striated
Voluntary Each fiber: Fusion of embryonic myoblasts Large Multinucleated Individually controlled Parallel to other fibers form bundles |
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Cardiac Muscle
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Myocardial celIs:
Short, striated, involuntary Branched- forms “fabric” intercalated discs between cells and connect them mechanically and electrically Not individually controlled |
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Smooth Muscle
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Not striated
Involuntary GI tract, blood vessels, bronchioles |
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Nervous Tissue
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neurons and supporting/glial cells
Neurons conduct electrical signals cell body, dendrites, and axon |
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Epithelial Tissue
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Lines and covers body surfaces
forms membranes and glands Regularly replaced Squamous epithelial cells- flattened Columnar epithelial cells- taller than wide Cuboidal epithelial cells- cube-shaped |
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Epithelial Tissue 2
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Simple membranes
one cell thick transport Stratified layers protection |
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Epithelial Tissue 3
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Non-keratinized
stratified squamous living cells Keratinized stratified squamous outer layer of dead cells keratin |
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Epithelial Tissue 4
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junctional complexes
strength, create barrier no room for vessels nutrients from tissue beneath basement membrane |
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Exocrine Glands
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Derived from epithelial cells
Secrete onto epithelium via ducts ex-lacrimal, sweat (vs secreting into blood-endocrine) simple tubes or acini, branched/unbranched |
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Connective Tissue
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extracellular material in spaces between cells
connective tissue proper, cartilage, bone, and blood CT Proper- collagen and gel-like ground substance Loose connective tissue Collagen |
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Adipose
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Loose CT
adipocytes fat synthesis, breakdown, and storage |
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Connective Tissue Proper
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Dense regular
Dense irregular Regular- parallel Ex- tendons Irregular Ex- capsules |
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Cartilage
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Support, protection
Chondrocytes surrounded by ground substance Precursor for bone Articular surfaces for joints |
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Bone
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Concentric layers , lamellae, of calcified material
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Organs
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anatomical and functional units
two or more primary tissues |
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Systems
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groups of organs working together to maintain homeostasis
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Skin
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cornified epidermis
Dermis Hypodermis |
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Stem Cells
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Most cells in organs are differentiated (highly specialized)
adult stem cells, (multipotent) vs totipotent vs pleuripotent) less differentiated; can become many cell types E.g. bone marrow stem cells can give rise to all of the different blood cell types |
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Nervous System (NS)
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Central nervous system (CNS)
and Peripheral Nervous System (PNS) |
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Central nervous system (CNS)
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Brain and Spinal Cord
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Peripheral nervous system (PNS)
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Cranial and Spinal Nerves
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Neurons
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are responsive cells in the nervous system that process and transmit information by electrochemical signaling.
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Structural Classification of Neurons
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Pseudounipolar:
Ex- sensory neurons Bipolar: Ex- retinal neurons Multipolar: Ex- motor neurons |
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Neurons 2
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Cell body nuclei and ganglia
Dendrites Axons Axon hillock |
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Functional Classification of Neurons
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Sensory/Afferent
Motor/Efferent Somatic Autonomic Sympathetic Parasympathetic |
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Somatic
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is the part of the peripheral nervous system[1] associated with the voluntary control of body movements through the action of skeletal muscles, and with reception of external stimuli, which helps keep the body in touch with its surroundings
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Autonomic
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is the part of the peripheral nervous system that acts as a control system, maintaining homeostasis in the body.
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Sympathetic
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It is always active at a basal level (called sympathetic tone) and becomes more active during times of stress. Its actions during the stress response comprise the fight-or-flight response.
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Parasympathetic
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The actions of the parasympathetic nervous system can be summarized as "rest and digest"
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Supporting/Glial Cells
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are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin, and participate in signal transmission in the nervous system.
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Schwann Cells
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are a variety of glial cell that mainly provide myelin insulation to axons in the peripheral nervous system (PNS) of jawed vertebrates.
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Myelination
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Neurilemma
Electrically insulates axon |
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node of Ranvier
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are the gaps (approximately 1 micrometer in length) formed between the myelin sheaths generated by different cells
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oligodendrocytes
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are a variety of neuroglia. Their main function is the insulation of the axons exclusively in the central nervous system of the higher vertebrates, a function performed by Schwann cells in the peripheral nervous system
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microglia
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are a type of glial cell that acts as the first and main form of active immune defense in the central nervous system (CNS).
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astrocytes
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are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical support of endothelial cells which form the blood-brain barrier, the provision of nutrients to the nervous tissue, and a principal role in the repair and scarring process of the brain and spinal cord following traumatic injuries.
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ependymal cells
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is the thin epithelial membrane lining the ventricular system of the brain and the spinal cord
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Membrane Potential (MP)
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is the voltage difference (or electrical potential difference) between the interior and exterior of a cell. Because the fluid inside and outside a cell is highly conductive, whereas a cell's plasma membrane is highly resistive, the voltage change in moving from a point outside to a point inside occurs largely within the narrow width of the membrane itself. Therefore, it is common to speak of the membrane potential as the voltage across the membrane.
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Excitability
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MP alters in response to stimulation to conduct impulses
Excitable cells Neurons, muscle fibers alter MP quickly By rapid changes in ion permeability |
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Depolarization
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is a decrease in the absolute value of a cell's membrane potential. Thus, changes in membrane voltage in which the membrane potential becomes less positive or less negative are both depolarizations.ΔMP = –70 to +30 mV
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Hyperpolarization
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is any change in a cell's membrane potential that makes it more polarized. That is, hyperpolarization is an increase in the absolute value of a cell's membrane potential. Thus, any change of membrane voltage in which the membrane potential moves farther from zero, in either a positive or negative direction, is a hyperpolarization
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Repolarization
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refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value. Repolarization results from the movement of positively charged potassium ions out of the cell. Typically the repolarization phase of an action potential results in hyperpolarization, attainment of a membrane potential that is more negative than the resting potential.
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leakage channels
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They form potassium-selective pores that span cell membranes. Furthermore potassium channels are found in most cell types and control a wide variety of cell functions.
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Voltage-gated (VG) channels
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transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. They play a crucial role during action potentials in returning the depolarized cell to a resting state.
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The Action Potential (AP)
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wave of MP change- moves along axon
Caused by rapid depolarization Na+ influx followed by rapid repolarization K+ efflux |
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Absolute refractory period
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is the interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied.
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Relative refractory period
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is the interval immediately following during which initiation of a second action potential is inhibited but not impossible.
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Unmyelinated Axon Conduction
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Myelin sheath
No APs under myelin, only at Nodes of Ranvier No current leaks current movement VG Na+ channels present only at nodes AP current at 1 node depolarizes next node to threshold Fast, APs skip node to node= saltatory conduction |
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Synapse
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Functional connection between
neuron (presynaptic) another cell (postsynaptic) chemical via neurotransmitters (NT) electrical rare in NS |
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Electrical Synapse
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gap junctions
connexin smooth and cardiac muscles, brain, and glial cells |
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Chemical Synapse
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are specialized junctions through which neurons signal to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form interconnected circuits within the central nervous system.
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Synaptic Transmission
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NT diffuses across cleft
Binds receptor proteins chemically-regulated ion channels open EPSPs (excitatory postsynaptic potentials) IPSPs (inhibitory postsynaptic potentials) IPSP and EPSP affect VG channels in postsynaptic cell EPSPs and IPSPs summate If MP in postsynaptic cell reaches threshold at the axon hillock, new AP is generated |
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synaptic vesicles
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store the various neurotransmitters that are released during calcium-regulated exocytosis at the presynaptic terminal into the synaptic cleft of a synapse.
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EPSPs
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Graded in magnitude
No threshold Cause depolarization Summate Have no refractory period |
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Spatial Summation
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Cable properties cause EPSPs to fade quickly over time and distance
Spatial summation EPSPs from different synapses at same time |
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Temporal summation
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EPSPs that occur closely in time can sum before they fade
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Acetylcholine (ACh)
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Most widely used NT
Brain, ANS, all neuromuscular junctions nicotinic and muscarinic receptor subtypes excitatory or inhibitory |
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Ligand-Gated Channels
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are a group of transmembrane ion channels that are opened or closed in response to the binding of a chemical messenger (i.e., a ligand),[1] such as a neurotransmitter.[2]
The direct link to an ion channel, which is characteristic of ligand-gated ion channels, is contrasted with the indirect function of metabotropic receptors, which use second messengers. Ligand-gated ion channels are also different from voltage-gated ion channels (which open and close depending on membrane potential), and stretch-activated ion channels (which open and close depending on mechanical deformation of the cell membrane). |
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G Protein-Coupled Channels
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are stimulated when the neurotransmitter binds to the G-protein coupled receptor (GCR). This activates G-proteins, which move to another ion channel. The G-Proteins allow the channel to open and ions are able to flow across the cell membrane. Because of the movement from the receptor to the ion, the speed of the channel opening is delayed, however the channel stays open for a longer time
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Acetylcholinesterase (AChE)
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is an enzyme that degrades (through its hydrolytic activity) the neurotransmitter acetylcholine, producing choline and an acetate group. It is mainly found at neuromuscular junctions and cholinergic synapses in the central nervous system, where its activity serves to terminate synaptic transmission. AChE has a very high catalytic activity — each molecule of AChE degrades about 5000 molecules of acetylcholine per second.
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Acetylcholine in the PNS
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end plates or neuromuscular junctions (NMJ)
Somatic motor neuron synapse with skeletal muscle Muscle fiber VG channels open Cause muscle contraction Curare competes with ACh for binding to nicotinic Ach receptor action at NMJ |
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Monoamine NTs
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Ex- serotonin, norepinephrine, dopamine
Serotonin derived from tryptophan Norepinephrine and dopamine derived from tyrosine catecholamines |
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Serotonin
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is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system (CNS) and enterochromaffin cells in the gastrointestinal tract of animals including humans.
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EEG Waves
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Beta Alpha Theta Delta
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Beta waves (F)
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visual stimuli, mental activity
13-25 cycles/sec |
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Alpha waves (P,O)
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awake, relaxed, eyes closed
8-12 cycles/sec |
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Theta waves (T,O
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Newborns
Awake Adults = severe emotional stress 5-8 cycles/sec |
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Delta waves (CC)
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Adult sleep, awake infants
awake adult = brain damage 1-5 cycles/sec |
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REM
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rapid eye movement
EEGs are similar to awake ones Dreaming Theta (5-8) |
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Non-REM
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Non-REM
Delta (1-5) Consolidation of short- into long-term memory |
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Functions of Cerebral Cortex Lobes
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Frontal, Parietal, Temporal, Occipital and Insula
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Frontal
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Motor control
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Parietal
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Somatasthetic
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Temporal
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Auditory
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Occipital
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Vision
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Insula
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Memory
Sensory + visceral Emption + visceral |
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Cerebral Lateralization
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Left hemisphere
language and analytical abilities Right hemisphere visuospatial tasks |
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Broca’s area
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Speech motor function (preCG)
Left inferior frontal gyrus |
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Wernicke’s area
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Speech motor function (preCG)
Left inferior frontal gyrus |
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Wernicke’s area
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Speech/Reading comprehension
Left superior temporal gyrus Arcuate fasciculus |
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Left Angular gyrus
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Integrates auditory, visual, and somatesthetic info
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Mirror Neurons
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In parietal and temporal lobes
Fire when observing others and when performing goal directed actions Required for empathy, social skills, language Some are found in Broca’s area |
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Limbic System, Hypothlalmus, & Emotion
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Aggression
Fear Feeding Sex Goal-directed behaviors Papez circuit Kluver-Bucy syndrome |
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Memory
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Short-term and long-term memory
Long-term memory Non-declarative (explicit) simple skills and conditioning Declarative (implicit) verbal memories Amnesiacs Semantic- fact Episodic- event |
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Memory & the Medial Temporal Lobe (Hippocampus, Amygdala)
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STM to LTM
Hippocampus New memories Left- verbal Right- nonverbal Amygdala fear memories |
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Memory & the Prefrontal Cortex
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memory storage
cerebral hemispheres Prefrontal cortex Higher order processing, problem solving, and planning Working memory |
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LTM
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permanent changes
protein synthesis and long term potentiation |
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Long term potentiation
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High frequency stimulation causes enhanced excitability
Hippocampus Glutamate NT |
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Glutamate NT
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Glutamate
Binds 3 receptors AMPA, NMDA |
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Neurogenesis in Hippocampus
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crucial for learning and memory
neural stem cells Effect of stress or depression on hippocampus Ex- PTSD |
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Thalamus
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Relays all sensory info (except olfactory) to cerebrum
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Epithalamus
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Choroid plexus
secretes CSF Pineal gland (epiphysis) secretes melatonin Reproduction, sleep |
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Hypothalamus
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Homeostasis!
Regulates sleep, emotions, etc., by working with limbic system Controls hormone release from anterior pituitary Visceral responses of emotions Produces ADH, oxytocin, GRH |
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Pituitary Gland
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anterior and posterior lobes
Posterior pituitary stores and releases ADH (vasopressin) and oxytocin |
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Circadian Rhythms
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suprachiasmatic nuclei of anterior hypothalamus
master clock, 24 hours retinohypothalamic tract Controls pituitary gland, pineal gland secretion of melatonin |
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Midbrain
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Corpora quadrigemina
Superior colliculi visual reflexes Inferior colliculi relay auditory information Substantia nigra of nigrostriatal system motor coordination Mesolimbic system |
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Mesolimbic system
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Mesolimbic dopamine neurons
reward and addiction dopamine release from the nucleus accumbens in forebrain |
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Respiratory Control Centers in Brain Stem
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3 respiratory control centers
Apneustic (pons) Pneumotaxic (pons) Rhythmicity center (medulla oblongata) |
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Cerebellum
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Proprioceptors (joint, tendon, and muscle receptors)
coordinating movements |
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Medulla Oblongata
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Contains all tracts that pass between brain and spinal cord
Some cranial nerves nuclei Vasomotor center Cardiac control center Rhythmicity center |
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Reticular Activating System (RAS)
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Sleep/Wake- dealing with sensory input
RAS neurons project to CC and control its arousal RAS Activation RAS Inhibition |
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Spinal Cord Tracts
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Sensory info
Body to brain ascending spinal tracts Motor activity Brain to body descending tracts |
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Ascending Spinal Tracts
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decussate
brain hemispheres receive info from opposite side of body Same for most descending tracts |
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Descending Spinal Tracts
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Pyramidal (corticospinal) tracts
No synapse between CC (preCG/motor cortex) and spinal cord Fine movements lateral corticospinal tracts Anterior corticospinal tracts Left hemi-skilled motor control of both hands |
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Descending Spinal Tracts continued
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Extrapyramidal (Reticulospinal) tracts
many synapses Originate in brain stem Controlled by caudate nuclues, putamen, and globus pallidus, substantia nigra, and thalamus Influence movement indirectly |
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Cranial Nerves
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12 pairs of nerves:
2 pairs forebrain 10 pairs midbrain and hindbrain Most mixed (sensory and motor fibers) olfactory and optic sensory only cell bodies in ganglia near the organ rather than in the CNS |
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Dorsal root
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sensory fibers
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Ventral root
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motor fibers
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Spinal Nerves
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31 pairs:
8 cervical pairs 12 thoracic pairs 5 lumbar pairs 5 sacral pairs 1 coccygeal pair |
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Common Features of ANS Regulation
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Smooth muscle
Resting tone (tension) Denervation hypersensitivity Intrinsic rhythmicity & contraction ANS neurotransmitters Acetylcholine (ACh) |
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Autonomic Neurons
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efferent pathway
preganglionic neuron autonomic ganglion postganglionic neuron |
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Divisions of the ANS
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Sympathetic-
Parasympathetic- |
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Sympathetic ANS
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thoracolumbar division
postganglionic neurons in the paravertebral ganglia sympathetic ganglionic chain |
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Sympathetic ANS 2
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white rami communicantes
gray rami communicantes mass activation |
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Sympathoadrenal System
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Adrenal glands
Cortex Steroid hormones Medulla modified sympathetic collateral ganglion secretory cells Modified postganglionic neurons Epinephrine Norepinephrine |
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Dually Innervated Organs
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Most visceral organs
Symp and Parasymp innervation usually antagonistic (heart rate) complementary cause similar effects (controlling salivation) cooperative produce different effects that work together to cause desired effect (male reproduction) |
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Organs Without Dual Innervation
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Sympathetic innervation only
adrenal medulla arrector pili muscle sweat glands most blood vessels Regulated by altering firing rate |
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Cholinergic and Adrenergic Stimulation
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Sym & Para preganglionic
ACh onto nicotinic receptors Para postganglionic ACh onto muscarinic receptors Most Sym postganglionic Norepinephrine onto adrenergic receptors |
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Neuroeffector Junctions
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Postganglionic autonomic neuron and target cell
Varicosity Vesicles filled with NTs release NT into the interstitial fluid |
