"The noblest pleasure is the joy of understanding."

- Leonardo Da Vinci

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Animal Physiology

Dr. Rai Khalid Farooqfarooq@asab.nust.edu.pk

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

(1)29

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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