INTRODUCTION Veterinary Physiology I Odd Semester 2015/2016 Division of Physiology Department of Anatomy, Physiology and Pharmacology FVM BAU 1
Main references: Cunningham, JG. 2002. Textbook of Veterinary Physiology Vander, Sherman, Luciano. 1990. Human Physiology Swenson M.J. and Reece. W.O.1993. Dukes Physiology of Domestic Animals. 2
PHYSIOLOGY The study of biological functions (generic) Could be defined more specifically in various ways: 1. The study of life processes that occur inside the body in all organizational levels: cell, tissue, organ, organ system, and the interaction between the units so that the organism as a whole could perform specific functions that are necessary for life 3
2. The study of cause and effect with emphasis on the how does this work? mechanism Example: a) What causes the heart to pump blood and what is the effect on circulation? b) What causes the pancreas to secrete the hormone insulin and what is the effect of this secretion to the blood glucose level? c) What causes perspiration after conducting acitivities? 4
Physiology requires a deep knowledge of anatomy Physiology requires knowledge of chemistry and physics Physiology is based on observations and accurate experimentation according to the principles of scientific methodology The terminal objective of researches in physiology is to understand the normal function of cells, organs, and organ systems 5
What is a living organism? An organism is an organised body, consisting of mutually connected and dependent parts constituted to share a common life. But what is life?
The characteristics of life (because there is not a single definition that can accurately describe them!) 1. Living organisms are highly organised 2. Homeostasis Maintaining a stable internal environment 3. Reproduction Making more of themselves with virtually perfect fidelity 4. Consuming energy and converting it from one form to another 5. Responding to stimuli 6. Adapted to their environments
There are other types of physiology: Pathophysiology the study of physiological processes when affected by injury or illness Exercise physiology the study of physiological processes when affected by exercise Comparative physiology the study of the physiology of different groups of vertebrate and avertebrate animals Ecophysiology the study pertaining to physiological process related to ecology 8
Much of the knowledge gained from comparative physiology has benefited mankind because many other animals, (particularly our closer relatives among Mammals) have the same or similar physiology. The small differences in physiology between human and other mammals can be of crucial importance in the development of pharmaceutical drugs, but these differences are relatively slight in the overall scheme of things 9
CELL ORGANIZATION Cell: the smallest units of an organism that has life characteristics Exchanges matter with the environment Receives energy from organic nutrients Synthesizes complex molecules Multiplies itself 10
Every organism began from a single cell: An ovum that is fertilized (zygote). One zygotic cell divides into 2,4,8 and so forth. During the development, each cell becomes specialized, having a certain function Cell differentiation: The transformation process from an unspecialized cell to a specialized cell 11
The cells that have differentiated and have similar characteristics will join and become a tissue. Various tissues join and form an organ. A number of organs together form a system. 12
Based on the function and location, in general, cells are classified into four categories: 1. muscle cells 2. nervous cells 3. epithelial cells 4. connective tissue cells 14
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MUSCLE CELLS Produce a power mechanism that results in force and movement. Related to the bones Attach to the skin expressions limb movement produce facial 16
Muscle Cells (continued) Coat a tubular structure pushes the contents contraction Cardiac pump Coating the blood vessel walls in diameter change 17
Nervous Cells Initiation and electrical conduction The signals cause glandular secretion or muscle contraction The main regulator of the activity of other cells Consciousness, perception, decision 18
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Epithelial Cells Specific for secretion and selective absorption of ions and organic molecules Covers the outer part of organs/tubular structures The basal membrane is selective (a barrier) 20
Connective Tissue Cells The connector, anchor, scaffolding; contains more extracellular material adipose tissue bone strong red blood cells, white blood cells collagen
Primary tissues Muscle tissue Nervous tissue Epithelial tissue Connective tissue 22
Tissue Structural Characteristics General Functions Specific Examples Epithelial Tightly packed cells; basement membrane, cuboidal, columnar, squamous shapes; simple of stratified. Protection, absorption, secretion, lines body surfaces Mucous membranes, maybe ciliated, lining of blood vessels Connective some cells that secrete extracellular matrix of protein fibers in liquid, gel or solid ground substance Connects and supports other tissues Loose connective tissue; adipose; fibrous connective tissue; cartilage; bone Muscle Long cell fibers with myosin and many microfilaments of actin Contraction, movement skeletal (voluntary control); smooth muscle (involuntary control) Nervous Neurons with cell bodies, axons, and dendrites Sense stimuli, conduct impulses Nerves and Brain, CNS & PNS
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ORGANS and SYSTEMS Organs are built from at least 2 but usually all 4 tissue primary types Each primary tissue contributes to the structure and function of each organ The largest organ (surface area) in the body is the skin 25
A system is a group of organs that are in different locations in the body but conduct functions that are related to one another The nervous system, the endocrinal system, the respiratory system, the cardiovascular system, the digestive system, the excretion system, the immune system, the reproductive system 26
THE ORGAN SYSTEMS System Primary organs or tissues Main function Circulation heart, blood vessel, blood, (lymph) Fast channeling of blood throughout the body Respiration Digestion Nose, pharynx, larynx, trachea, bronchi, lungs Mouth, pancreas, liver, gall bladder, pharynx, esophagus, stomach, intestines, salivary glands, CO2 and O2 exchange, regulation of H ion concentration Digestion and absorption of organic nutrients, minerals and water 27
THE ORGAN SYSTEMS( continued) System Primary organs or tissues Main function Excretion Kidney, urether, bladder, urethra Regulating the plasma composition through regulation of the excretion of organic wastes, salt, and water Skeletal muscles Cartilage, bone, ligament, tendon, joint, skeletal muscles Supporting and protecting, body mobility Immune WBC, lymph vessel and nodes, spleen, thymus, and other lymphatic tissues Defense against invasion, returing extracellular fluids to the blood, production of WBC 28
THE ORGAN SYSTEMS( continued) System Primary organs or tissues Main function Nervous Endocrine Brain, spinal cord, peripheral nerves and ganglia, sensory organs All the glands that produce hormones: the pancreas, testes, ovaries, hypothalamus, hypofisis, kidney, thyroid, parathyroid, adrenal, intestines, thymus and pineal gland Regulation and coordination of many activities in the body, detecting changes in the environment (internal and external), awareness status, learning, cognition Regulating and coodinating many activities in the body 29
THE ORGAN SYSTEMS( continued) System Primary organs or tissues Main function Reproduction Male: Testes, penis, accessory glands and ducts. Producing sperm, transfering sperm to the female Female: Ovaries, oviduct, uterus, vagina, mammary gland Producing ova, supplying foor for the embryo and fetus, and providing nutrients the young Integumen Skin Protection of the internal parts of the body 30
Integration and Coordination between Organ Systems
HOMEOSTASIS The study of Physiology usually revolves aroud the concept of Homeostasis. o the term was coined by the Founder of Modern Physiology : Claude Bernard (1813-1878, France) o homeo Greek, same or similar o stasis Greek, fixed or stationary. Homeostasis The organism s tendency to regulate and maintain its internal condition at a relatively stable state so that it could survive even though there are changes inside and outside its body. Homeostasis is controlled by the nervous and endocrinal systems.
Cells experience a relatively stable (constant) environment in terms of temperature, ph, glucose concentration, oxygen level, etc. Example: the body temperature is maintained at 37 C (98.6 F) regardless of the temperature outside the body.
Because the body consists of 75 trillion cells, the survival of the body is the survival of all of these cells. All bodily processes collaborate in maintaining internal cell homeostasis so that we can live. All the needs of the cells are supplied by the external environment (water, food, minerals, oxygen), but because the cells do not have direct contact with the external environment, there must be a way to exchange substances and to obtain what is needed by the cells in order to survive and to dispose waste (substanced that are not needed)
THE HOMEOSTATIC MECHANISMS Claude Bernard (19th century): Homeostasis W. B. Cannon (20th century): a dynamic balance Negative Feedback Mechanism Positive Feedback Mechanism For example: the secretion of hormones during ovulation and partus In addition, there is a positive feedback mechanism the increase in LH during the periovulatory phase is due to the increased production of estrogen by the follicle(s)
1.9 Negativedback Homeostasis depends on Negative feedback comparator
A. The Components of the Homeostatic Control System Reflexes Local Homeostatic Responses Chemical Substances as Intercellular Messengers Hormones Neurotransmitters Neurohormones Paracrines Eicosanoids Prostaglandin Prostacycline Tromboxan Leucotrien
The Reflex Arc Integration Center Afferent Path Efferent Path Receptor Effector Stimulus Response
An example of homeostasis: Body Temperature Regulation Reflex Integration center: specific nerve cells in the brain Temperature-sensitive nerve endings Smooth muscles in skin blood vessels skeletal muscles Body temperature Blood vessels contract Heat loss Shivering Heat production