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PhysiologyPhysiology
Carla Thompson
Talmage Harrold
Lydia McDore
•The study of processes and functions, incidental to, and characteristic of, life. •Physiology is an integrative science; examining body operation at all levels of organization, from cells to organs.•Homeostasis, flexibility, cell-to-cell communication, information transfer across cell membranes, energy flow in biological systems, and mass balance are six major themes in physiology.
http://cwx.prenhall.com/bookbind/pubbooks/silverthorn2/www.brainydictionary.com
Introduction to Physiology
The Nervous System
• Central Nervous System consists of the brain and spinal cord.
• Peripheral nervous system consist of the cranial nerves, the spinal nerves, and visceral nervous system.
• The Neuron is an individual nerve cell.
http://cas-cousres.buffalo.edu/classes/phy/segal/2472000/247neuro.htm
The Neuron•Types of Neurons
•Afferent Neurons (sensory) transmit information from tissues and organs into the central nervous system.•Efferent neurons (Motor) convey signals from the central nervous system to the effector cells. •Interneuron connect neurons within specific regions of the central nervous system.
•Parts of the Neuron•Axon carries synapse away from the cell body. •Dendrite receive synaptic information and it travels toward the cell body. •Cell Body (Soma) where information is integrated into the neuron.
http://en.wikipedia.org/wiki/Neuron
http://distance.stcc.edu/aandp/AP/AP1pages/nervssys/unit10/neurons.htm
Nerve Conduction• Neurons are specifically designed to transmit
information.• Presynaptic neurons send the neuron.• Postsynaptic neurons receive the neuron. • Active neurons (excitatory) produce an action
potential which travels down the neuron.• A synapse releases neurotransmitters that
change the electrical potential of the next neuron.
• Inactive neurons (inhibitory) simply do not react.
http://cas-cousres.buffalo.edu/classes/phy/segal/2472000/247neuro.htm
Curare• Comes from two South
American plants Strychnos taxifera and Chondrodendron tomentosum.
• A muscle relaxer used in anesthesia.
• Blocks acetycholine (ACh) receptors on the postsynaptic membrane of the neuromuscular junction.
http://en.wikipedia.org/wiki/Curare
Myelination
• The process in which reserve cells are covered by and insulated with a layer of fat cells.
• Increases the speed of information which travels through the peripheral nervous system.
www.mc.maricopa.edu/dept/d46/psy/dev/fall99/prenatal/brain.html
All-or-None Principle • Action potentials are approximately equal in size
and shape (amplitude) under normal circumstances.
• The size and shape of the action potential are independent of the intensity of the stimulus that initiated it.
• Temporal summation is the process whereby a stimulus that is below threshold will elicit a reflex if the stimulus occurs repeatedly.
• Spatial summation is the process whereby two or more stimuli that are individually below threshold will elicit a reflex if they occur simultaneously at different points on the body.
http://www.miracosta.cc.ca.us/home/sfoster/neurons/glossary.htm http://www.wwnorton.com/college/pysh/gman5/glossary/T.htm
Brains and Evolution
• Physical factors and time are constraints against evolutionary changes for the brain.
• The nearer to the front of the brain we go, the ‘newer’ it is.
• The hindbrain controls more primitive functions- - heart rate and breathing- - where as the forebrain controls more thought and logical patterns– - -planning and behavior.
The Brain
Left
Hemisphere
Controls the right side of the body.
Bilateral symmetry
Right
Hemisphere
Controls the left side of the body.
Lobes of the Brain
Brain OrganizationBrain Organization Medulla oblongata- breathing and heart rateMedulla oblongata- breathing and heart rate Pons- Sleep and arousalPons- Sleep and arousal Cerebellum- voluntary muscle control and motor Cerebellum- voluntary muscle control and motor
coordination coordination Hypothalamus- links autonomic nervous system to Hypothalamus- links autonomic nervous system to
endocrine system, growth, living, and emotions.endocrine system, growth, living, and emotions. Thalamus- relays input from senses to higher Thalamus- relays input from senses to higher
structuresstructures Hippocampus- processes memoriesHippocampus- processes memories Cerebral cortex (Neocortex)- organizes Cerebral cortex (Neocortex)- organizes
information and initiates responses. information and initiates responses.
Colliculi
Superior colliculus- hand-eye coordination
rapid eye movementInferior colliculus- receives
input from auditory stimulus, controls your response to loud noises
http://en.wikipedia.org/wiki/SuperiorColliculi
Endocrine SystemEndocrine System
Secretes hormonesSecretes hormones
Hormones are chemicals secreted by Hormones are chemicals secreted by endocrine glands that are carried through endocrine glands that are carried through the bloodstream to affect various body the bloodstream to affect various body parts.parts.
Endocrine System Con’tEndocrine System Con’t Pituitary gland- master gland, in brain, which secretes Pituitary gland- master gland, in brain, which secretes
releasing hormones that “turn on” other endocrine releasing hormones that “turn on” other endocrine glands.glands.
Thyroids- in neck, produce thyroxin which regulates Thyroids- in neck, produce thyroxin which regulates
growth, activity levels and metabolismgrowth, activity levels and metabolism. . Adrenals- near kidney, produce ACTH outside the gland, Adrenals- near kidney, produce ACTH outside the gland,
produce adrenaline/ noradrenalin inside the gland.produce adrenaline/ noradrenalin inside the gland. Pancreas- near stomach, produces insulin and glucogen.Pancreas- near stomach, produces insulin and glucogen.
IInsulin- glucose absorbtion mechanismnsulin- glucose absorbtion mechanism
Glucogen- hypoglycemiaGlucogen- hypoglycemia
Sex glands- ovaries and testesSex glands- ovaries and testes Ovaries-produce estrogen and progesteroneOvaries-produce estrogen and progesterone Testes- produce testeroneTestes- produce testerone
Natural SelectionNatural Selection
• Nature selects the best Nature selects the best adapted varieties to adapted varieties to survive and to survive and to reproduce. Darwin reproduce. Darwin called this “survival of called this “survival of the fittest.”the fittest.”
http://anthro.palomar.edu/evolve/evolve_2.htmhttp://anthro.palomar.edu/evolve/evolve_2.htm