ORGANIZATION OF REGULATION OF THE HUMAN BODY
I. Organization of Life
A. Structure:Function and Function:Structure
1. Anatomy - study of the structure of cells, tissues, organs, organisms
2. Physiology - study of how cells, tissues, organs, organisms function
3. Darwin - Origin of the Species (1858) and the Theory of Evolution demonstrated
a. Structure and Function are intimately linked
b. Structure dictates the Function
1. Adaptation influence Niche: Finch beaks and food on the Galapagos
c. Evolution "selects" most favorable Functions
1. kidneys/skin of various organisms
a. kangaroo rat – desert adaptations
b. human – land
c. sea bass - salty ocean water adapted
d. Environment and competition "naturally" select genes that give rise to Structures that have
favorable Functions to improve the viability of each species
B. Organization of Living Things
1. principles of matter/energy
(Physics)
2. atoms -> molecules
(Chemistry)
3. complex organic molecules
(Biochemistry)
4. organelles -> cells
(Cellular Biology)
5. tissues
(Histology)
6. organs
(Physiology/Anatomy)
7. organ/body systems
(Physiology/Anatomy)
8. organism
(Physiology/Anatomy)
*** all fields overlap and contribute to each other
II. Basic Functions of Organisms involves the Organ Systems What Do Organ Systems Do?
A. Maintenance of Boundaries stable internal conditions - separation of organism from outside world
protection from pathogens. Protect the body against injury and attack
a cell - cell membrane (semipermeable - selective)
b. organism – skin and immune system.
B. Movement - ability to move self and materials
a. cells - cilia and flagella (sperm)
b. humans - muscle cells (contractility) & bone
C. Responsiveness (Irritability) - respond to both Internal and External changes
a. nervous system - quick response to change
b. endocrine system - medium/longer changes
D. Acquire nutrients and raw materials; dispose of wastes through
a. digestive system - breakdown/absorb essential materials
E. Metabolism - all chemical reactions that occur in cells & body
a. anabolism - synthesizing larger molecules
b. catabolism - breaking down large molecules
c. regulated primarily by endocrine hormones
d. Enzymes are proteins that speed up rates of reaction
Enzymes Support Metabolism: HOW??
• Protein molecules that catalyze the reactions of living organisms.
• Enzymes increase the rate of a chemical reaction without being consumed in the process.
• Name: Substrate (or activity) + ase suffix
Examples: Sucrase breaks down sucrose; Lipase breaks down _________?
– Proteinase breaks down _________? Dehydrogenase (Removes H atoms)
• Enzymes are specific: Catalyze one or a few related reactions.
• Enzymes are efficient. Can increase the rate of a reaction 10 to billions of times!!!!
CELLULAR RESPIRATION IS A SERIES OF CHEMICAL REACTIONS, EACH REACTION UTILIZES A
SPECIFIC ENZYME - breaking bonds of larger molecules to acquire useable energy currency (ATP)
involves these organ systems: GLUCOSE + OXYGEN  CARBON DIOXIDE + WATER + ENERGY
(stored in ATP).
Cell Respiration uses these three organ systems.
a. digestive system - mainly carbohydrate & fats
b. respiratory system - oxygen and carbon dioxide
c. cardiovascular system - distribution of nutrients and gases
Remember
this
equation:
GLUCOSE + OXYGEN  CARBON DIOXIDE + WATER + ATP
Cell Respiration in the presence of oxygen Makes 32-38 molecules of ATP for each glucose
Anaerobic Conditions lead to Fermentation: the breakdown of sugar in the absence of oxygen. Produces
2 ATP per molecule of Glucose. Lactic Acid is formed.
Environmental Factors Affect Enzyme Function and therefore the Rates of Chemical
Reactions in the Body:
A. Temperature: Optimal temperature.
– Most reactions are too slow at low temperatures.
– Most enzymes are denatured over 50-60oC.
B. Salt concentration: Optimal concentrations vary for each enzyme.
C. pH: Optimal pH varies, but most enzymes work best close to pH 7.
• Pepsin optimal pH is 2
• Amylase optimal pH is 8.5
D. Other essential molecules are required by some enzymes:
• Cofactors: Inorganic atoms that must bind (Cu, Fe, Zn)
• Coenzymes: Organic compounds that must bind (vitamins)
Acquisition and Utilization of Energy : ATP powers nearly all forms of cellular work:
1. Mechanical work: Muscle contraction, beating of flagella and cilia, cell movement, movement of
organelles, cell division.
2. Transport work: Moving things in & out of cells.
3. Chemical work: All endergonic reactions.
F. Excretion - removing all types of waste from the body
a. digestive system - unused foodstuffs
b. urinary system - nitrogenous wastes (urea) and electrolyte (salt) balance
c. respiratory system - carbon dioxide
G. Reproduction - creating more organisms of the same species
a. virus - depends on cells for their machinery
b. cells - the process of division (mitosis)
c. human - sexual (sperm and egg)
i. regulated by hormones (especially female)
H. Growth - increase in size of cell, organ, or organism
a. number of cells can increase (mitosis)
b. size of cells can increase (fat cells)
III. Basic Biological Needs of Humans
A. Nutrients - molecules for structure and energy
1. carbohydrates - primary energy source & structural
a. glycogen, sugars (glucose)
2. proteins - primarily structural & for signaling (hormones and receptors)
a. 20 amino acids are basic building blocks
b. actin and myosin microfilaments of muscle
c. receptors for hormones/neurotransmitters
d. neuropeptides (enkephalins of nervous system)
3. fats (lipids) - insulation, energy, structure
a. major component of membranes (phospholipids)
b. highest energy content by weight (calories)
4. Coenzymes: like vitamins – organic (Carbon containing) molecules that act as cofactors for enzyme
functioning
5. Cofactors like minerals – inorganic ions and atoms essential for signaling and structure
a. nerve signals - Na+, K+, Ca+, Clb. carry oxygen - Fe++ in hemoglobin
c. bone - Ca++ Phosphates
B. Oxygen - essential for maximum energy gain from food
1. cellular respiration depends on oxygen
2. nervous system alone uses 25% of all oxygen in humans
C. Water - essential for cellular reactions and transport. Cells are composed of more than 70% water.
D. Body Temperature - essential for cellular reactions,
.
Above 112 F is lethal. Enzymes DENATURE (change their shape)
E. Atmospheric Pressure - for proper absorption of oxygen
Physiology is the study of how organisms separate self and non-self; move; respond to internal
and external changes; digest, metabolize, and excrete materials; reproduce; and grow.
This is achieved by maintaining a proper BALANCE both internally and with the outside world.
IV. Homeostasis: The ability of the body to maintain a relative constancy of internal environment in response to
internal and external changes by adjusting its physiological processes
- dynamic process; changing but relatively constant within limits
- concerns all factors relating to well being of organism (see above)
- regards maintaining internal environment of body due to internal and external changes
1. Homeostasis refers especially to maintenance of proper conditions for:
a. oxygen (O2) and carbon dioxide (CO2) levels
b. levels of nutrients in blood (e.g. glucose)
c. electrolyte /salt balance and osmotic pressure (fluid levels)
d. acid-base balance (pH)
e. temperature
f. pressure of body cavities (especially lungs)
Examples of homeostatic mechanisms:
1. proper sugar (nutrient) levels in the blood uses hormones. insulin/glucagon - blood glucose levels
2. proper heart rate and blood pressure uses hormone adrenaline - response to stimuli
3. removing wastes from the blood involves
a. kidneys processing - nitrogenous wastes (urea) and b. respiratory - carbon dioxide
4. maintaining proper oxygen levels in blood involves signals from brain influencing respiration - adjust breathing
rate
5. body posture and simple muscular reflexes involves interactions of nervous system and muscular system
B. GENERAL CHARACTERISTICS OF HOMEOSTATIC CONTROL MECHANISMS
1. Nervous & Endocrine Systems provide general controls
2. Basic Organization of Control Mechanisms
a. receptor - monitors internal/external stimuli sends info to control center via afferent path
b. control center (nervous system) - analyzes info as it compares to a "set point" for that particular
variable
1. variables may include: glucose level, heart rate, blood pressure, urea concentration,
oxygen level, tension on a muscle.
c. effector - physiological mechanism acting from the control center via efferent path
C. Negative Feedback Mechanisms
1. control mechanism DECREASES intensity of condition to bring back to "set point"
example: regulation of glucose levels in blood
a. person eats a candy bar with lots of sugar
b. glucose levels in the blood rise rapidly
c. receptors sense increase in blood sugar
d. control center calls for reduced blood sugar
insulin is secreted into the blood stream
e. insulin causes effector cells (liver & muscle) to absorb glucose and store it as glycogen
- glucose levels return to normal (0.9 mg/ml blood)
D. Positive Feedback Mechanisms (cascade - like a snowball effect)
1. control mechanism INCREASES intensity of condition - causing a "domino" effect. Example: labor
contractions during birth
a. baby rotates into cervix causing pressure
b. receptors sense increased muscle tension
c. control center calls for release of oxytocin, causing muscles (effectors) to contract more
d. increased muscle tension causes receptors to continue the message to the control center
e. more oxytocin is released
f. loop continues until baby is delivered and the stimulus is no longer present
In Physiology, we study how each of the organ systems work to provide survival
needs of organism and maintain homeostasis of each of the essential variables !!!!!