"the noblest pleasure is the joy of understanding." - leonardo da vinci
TRANSCRIPT
"The noblest pleasure is the joy of understanding."
- Leonardo Da Vinci
Physiology
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• A sub-discipline of biology, its focus is in how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system
• Animal physiology (including that of human)• Plant physiology• Cellular physiology• Microbial physiology (see microbial metabolism)• Bacterial and viral physiology• Nobel Prize in Physiology or Medicine is awarded to those who make significant
achievements in this discipline since 1901 by the Royal Swedish Academy of Sciences
In medicine, a physiologic state is one occurring from normal body function, rather than pathologically.
Dilemma of form & function
Physiology from Ancient Greek (physis), meaning "nature, origin", and (-logia), meaning "study of” is the scientific study of normal function in living
systemsPhysiology is the study of mechanical, physical and biochemical properties of living organisms, it incorporates a significant amount of anatomy, the science
of body structure and their inter-relationship
Levels of organization of human body
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Molecular compositionof the human body
Water67%
Proteins20%
Carbohydrates 3%
Lipids10%
Elemental compositionof the human body
Hydrogen62%
Oxygen26%
Carbon10%
Nitrogen1.5%
Other Elements:
CalciumPhosphorusPotassiumSodiumSulfurChlorineMagnesiumIronIodineTrace elements
0.2%0.2%0.06%0.06%0.05%0.04%0.03%0.0005%0.0000003%(see caption)
Chemical and Molecular Level
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Levels of Organization: Cellular
• Basic units of structure and function
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Levels of Organization: Tissue Epithelial tissue Connective tissue Muscle tissue Nervous tissue
• Cells with similar functions grouped into the 4 primary tissues
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Skin—The Largest Organ
• Outer layer of protective cornified epidermis • Next layer the dermis contains connective tissue, glands, blood
vessels (BVs), nerves• Inner layer the hypodermis contains adipose tissue, BVs, nerves
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Stem Cells
• Most cells in organs are highly specialized or differentiated
• Many organs retain small populations of adult stem cells– less differentiated so can become many cell typesExample: bone marrow stem cells can give rise to all of the different
blood cell types
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Body-Fluid Compartments
• Our body has both intracellular and extracellular compartments:Intracellular - inside cells (cytoplasm)Extracellular - outside cells (blood plasma, interstitial fluid)
• Compartments separated by the cell’s plasma membrane
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• Respiratory system– O2
Gastrointestinal tract– Carbohydrates– Fatty acids– Amino acids– Others
Liver& other organs– Substances into useable forms
Origin of Nutrients in the Extracellular fluid
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• Musculoskeletal system
Removal of Metabolic End–products.• CO2 (by lung)• Urea, uric acid, excess water and ions • (kidneys)• others Regulation of body functions.• Nervous system
– Sensory input portion– CNS– Motor output portion
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Origin of Nutrients in the Extracellular fluid
• Hormonal system• Reproductive system
100 Trillion of Cells Organs Internal environment Homeostasis
Automaticity of body
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Origin of Nutrients in the Extracellular fluid
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Levels of Organization: Organ System
Chemical orMolecular Levels
Atoms incombination
Complex proteinmolecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiacmuscletissue
OrganLevel
Cardiovascular
Reproductive Urinary
Digestive Respiratory
Lymphoid Endocrine Nervous
Muscular Skeletal
Integumentary
OrganismLevel
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• Organs located in different regions of the body that perform related functions are grouped into systems
Organ System Level
Cardiovascular
Reproductive
Urinary
Digestive Respiratory
Lymphoid Endocrine Nervous
Muscular Skeletal
Integumentary
OrganismLevel
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Levels of Organization: Organ System
Organismal Level
Chemical levelAtoms combine to form molecules.
Cellular level Cells are made up of molecules.
Tissue levelTissues consist of similar types of cells
Organ levelOrgans are made up of different types of tissues.
Organ system level Organ systems consist of different organs that work together closely.
Organismal levelThe human organism is made up of many organ systems.
Cardiovascular system
OrganelleMoleculeAtomsSmooth muscle cell
Smooth muscle tissue
Connective tissue
Blood vessel(organ)
HeartBloodvessels
Epithelialtissue
Smooth muscle tissue
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Cellular functions
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ProtoplasmWater
Ions
ProteinsCarbs
Lipids
Cell membrane
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Transport of ions & molecules through the cell membrane
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Chemical composition of extracellular &intracellular fluid
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Movements Into & Out of the Cell
Passive (Physical)
Require no cellular energy
• Simple diffusion
• Facilitated diffusion
• Osmosis
• Filtration
Active (Physiological)
Require cellular energy
• Active transport
• Endocytosis
• Exocytosis
• Transcytosis28
Simple Diffusion
• Movement of substances from regions of higher concentration to regions of lower concentration
• Oxygen, carbon dioxide and lipid-soluble substances
Time
Solute molecule
Water molecule
A B A B
(2) (3)
Permeablemembrane
A B
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Facilitated Diffusion
• Diffusion across a membrane with the help of a channel or carrier molecule
• Glucose and amino acids
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Osmosis and Osmotic Pressure
Osmotic Pressure – ability of osmosis to generate enough pressure to move a volume of water
Osmotic pressure increases as the concentrationof nonpermeable solutes increases
• Isotonic – same osmotic pressure
• Hypertonic – higher osmotic pressure (water loss)
• Hypotonic – lower osmotic pressure (water gain)
(b)
(a)
(c)
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Filtration• Smaller molecules are forced through porous
membranes
• Hydrostatic pressure important in the body
• Molecules leaving blood capillaries
Capillary wall
Larger molecules
Smaller molecules
Bloodpressure Blood
flow
Tissue fluid
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Active Transport
• Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration
• Sugars, amino acids, sodium ions, potassium ions, etc.
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Active Transport: Sodium-Potassium Pump
• Active transport mechanism
• Creates balance by “pumping” three (3) sodium (Na+) OUT and two (2) potassium (K+) into the cell
• 3:2 ratio
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Secondary Active Transport• Uses the energy stored in a concentration gradient
– the gradient is established through active transport
• Symporters move substances in the same direction while • Antiporters move substances in opposite directions
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Endocytosis• Cell engulfs a substance by forming a vesicle around the
substance
• Pinocytosis – substance is mostly water• Phagocytosis – substance is a solid• Receptor-mediated endocytosis – requires the substance to
bind to a membrane-bound receptor
Particle VPhagocytizedparticle
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Exocytosis
• Reverse of endocytosis• Substances in a vesicle fuse with cell
membrane• Contents released outside the cell• Release of neurotransmitters from nerve cells
Nucleus
Endoplasmicreticulum
Golgiapparatus
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Transcytosis
• Endocytosis followed by exocytosis• Transports a substance rapidly through a cell• HIV crossing a cell layer
Viruses budHIV
Exocytosis
Receptor-mediated endocytosis
HIV-infectedwhite blood cells Anal or
vaginal canal
Lining of anusor vagina(epithelial cells)
Virus infectswhite blood cells onother side of lining
Receptor-mediatedendocytosis
Cellmembrane
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Basics of anatomical terminology
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