Download Physiology Assumptions in Physiology Organization of the Body

Introduction to Physiology and
Homeostasis
Physiology
• Physiology is the study of how
how living organisms function
Chapter 1
Assumptions in Physiology
• The same chemical and physical laws that apply to the inanimate world govern processes in the the living body. • The laws describe how
how an organism lives using information from biology, chemistry, physics, and mathematics
– Not concerned with that part of life which cannot be explained by science
– On the street explanations are in terms of meeting a bodily need
– Physiologic explanations emphasize how how something occurs and how
how its occurrence contributes to the maintenance of normalcy i.e. the homeostatic condition known as life
Organization of the Body
• Levels of organization
– Chemical • An organism is ultimately a set of highly organized, elegantly interacting, organic
organic molecules
• Molecules composed of atoms
– Cellular • Cells are basic unit of life
• Cells must perform certain functions to maintain “live”
status
– Each cell contributes to the continued existence and possible demise of the organism
– Must obey basic laws of thermodynamics
– Cells exist at expense of surrounding environment
Organization of the Body
(a) Chemical level: a molecule in
the membrane that encloses a cell
(b) Cellular level: a cell
in the stomach lining
• Levels of organization
(c) Tissue level: layers of
tissue in the stomach wall
– Cells make up
• Tissue
– Tissues make up
(d) Organ level:
the stomach
• Organ
– Organs make up
(e) Body system
level: the digestive
system
• Body system
– Body systems make up
• Organism
(f) Organism level:
the whole body
Fig. 1-1, p. 3
Basic Functions of Living Cells
1. Obtain nutrients and oxygen from surrounding environment
2. Perform chemical reactions that provide energy for the cell
a. Food + O2  CO2 + H2O + energy
3. Eliminate carbon dioxide and other wastes to surrounding environment
4. Synthesize needed cellular components
Basic Functions of Living Cells
4. Control exchange of materials between cell and its surrounding environment
5. Monitor, detect and respond to change surrounding environment
6. Reproduction
a. Exception: Nerve cells and muscle cells lose their ability to reproduce during their early development
Specialized Cell Functions
• Multicellular organisms – cells also perform specialized functions that contribute to the life of the organism
– Specialized functions are modifications of some basic function
• e.g. Digestive enzymes • Basic functions = individual cell survival
• Specialized functions = survival of organism
Tissues
• Groups of cells with similar structure and specialized function
• Four primary types of tissues
– Muscle tissue
– Nervous tissue
– Epithelial tissue
– Connective tissue
Tissues
• Muscle tissue
– Specialized for contracting which generate tension and produce movement
– Skeletal muscle
– Moves the skeleton
– Cardiac muscle
– Pumps blood out of the heart
– Smooth muscle
– Encloses and controls movement of contents through hollow tubes and organs
Tissues
• Nervous tissue
– Consists of cells specialized for initiating and transmitting electrical impulses
– Found in brain, spinal cord, and nerves
• Epithelial tissue
– Consists of cells specialized for exchanging materials between the cell and environment
– Structures: Epithelial sheets & secretory
glands
Tissues
Organs
• Connective tissue
– Connects, supports, and anchors various body parts
– Distinguished by having relatively few cells dispersed within an abundance of extracellular material
– Examples: Tendons, bone, blood • Two or more types of primary tissues that function together to perform a particular function or functions
• Example: Stomach
• Inside of stomach lined with epithelial tissue
• Wall of stomach contains smooth muscle
• Nervous tissue in stomach controls muscle contraction and gland secretion
• Connective tissue binds all the above together
Organ:
Body structure that integrates different
tissues and carries out a specific function
Surface epithelium
Stomach
Duct cell
Secretory exocrine
gland cell
Connective tissue: Muscle tissue:
Epithelial tissue:
Protection, secretion, Structural support Movement
and absorption
Nervous tissue:
Communication,
coordination,
and control
Fig. 1-2, p. 4
(a) Exocrine gland
Fig. 1-3a, p. 4
Body Systems
Surface epithelium
Secretory endocrine
gland cell
Blood vessel
• Groups of organs that perform related functions and interact to accomplish a common activity essential to survival of the whole body
• Do not act in isolation from one another
• Human body has 11 systems
(b) Endocrine gland
Fig. 1-3b, p. 4
Body Systems
1.
2.
3.
4.
5.
6.
Circulatory System
Digestive System
Respiratory System
Urinary System
Skeletal System
Muscular System
7. Integumentary
System
8. Immune System
9. Nervous System
10. Endocrine System
11. Reproductive System
Circulatory system
heart, blood
vessels, blood
Digestive system: Respiratory system
mouth, pharynx, nose, pharynx,
esophagus,
larynx, trachea,
stomach,
bronchi, lungs
small intestine,
large intestine,
salivary glands,
exocrine pancreas,
liver, gallbladder
Urinary system
kidneys, ureters,
urinary bladder,
urethra
Skeletal system Muscular system
bones,
skeletal muscles
cartilage,
joints
Fig. 1-4a, p. 6
Homeostasis
• Defined as maintenance of a relatively stable internal environment (EXTRACELLULAR FLUID)
– The internal enviroment is the EXTRACELLULAR FLUID
• Each cell’s activity somehow contributes to maintenance of a relatively stable internal environment
• Each cell’
Each cell’s activity somehow contributes to upset of internal environment
• Homeostasis is maintained by multifaceted, interacting, “mechanisms”
mechanisms”
Nervous system
Integumentary system Immune system
skin, hair, nails
lymph nodes, thymus, brain, spinal cord,
bone marrow, tonsils, peripheral nerves,
and, not shown,
adenoids, spleen,
special sense
appendix, and,
organs
not shown, white
blood cells,
gut-associated
lymphoid tissue
Endocrine system
all hormone-secreting
tissues, including
hypothalamus, pituitary,
thyroid, adrenals,
endocrine pancreas,
gonads, kidneys,
pineal, thymus, and,
not shown, parathyroids,
intestine, heart, skin,
adipose tissue
Reproductive system
Male: testes, penis,
prostate
gland, seminal
vesicles,
bulbourethral glands,
and associated ducts
Female: ovaries,
oviducts,
uterus, vagina, breasts
Fig. 1-4b, p. 6
Homeostatic Control Systems
• In order to maintain homeostasis, control system must be able to
– Detect deviations from normal in the internal environment that need to be held within narrow limits
– Integrate this information with other relevant information
– Make appropriate adjustments in order to restore factor to its desired value
– In introductory physiology one studies and attempts to learn the
mechanisms involved in these multifaceted, interacting control systems mechanisms involved in these multifaceted, interacting control systems which function to maintain homeostasis
– In introductory physiology, study is organized by systems for the In introductory physiology, study is organized by systems for the convenience of the learner
• In nature the systems interact automatically and in a hierarchy that results in In nature the systems interact automatically and in a hierarchy that results in survival of the organism