Chpt 1: Functional Organisation Of The Human Body And Control Of The "Internal Environment" Flashcards
physiology is
the science that seeks to explain the physical and chemical mechanisms that are responsible for the origin, development, and progression of life
Field of physiology is divided into
viral physiology bacterial physiology cellular physiology plant physiology invertebrates physiology vertebrate physiology mammalians physiology Human physiology etc
Human physiology
explains the specific characteristics and mechanisms of the human body that make it a living being
cell
is the basic unit of the body
organ
it’s an aggregate of different cells held together by intercellular supporting structures.
number of RBCs in the human body
25 trillion in each human
function of RBCs
transport oxygen from the lungs to the tissues
total number of cells in the body
25 trillion RBCs
75 trillion additional cells of other types
therefore the entire body contains about 100 trillion cells
basic similar characteristics of all cells
1) oxygen reacts with carbohydrate, fats, and proteins to release energy required for cell functions.
2) general chemical mechanisms for changing nutrient into energy
3) deliver products of their chemical reactions into surrounding fluids.
4) ability to reproduce cells of the own kind
what percentage of the human body is fluid
60% mainly of water solution containing ions and other substances.
two types of fluid
intracellular fluid: fluid inside the cells
extracellular fluid: one-third of the fluid present outside the cell.
extracellular fluid
is in constant motion through out the body. it is transported in the circulating blood and then mixed been blood and tissue fluid by diffusion through the capillary walls.
what does extracellular fluid contain
ions and nutrients needed by the cells to maintain life.
extracellular fluid also called as
“internal environment”of the body or “milieu intérieur” term introduced 150 years ago by 19th century French physiologist Claude Bernard.
why is extracellular fluid called internal environment?
because all cells live in essentially the same environment- the extracellular fluid.
cells are capable of living and performing their functions as long as
the proper concentration of: 1. Oxygen 2. glucose 3. different ions 4. amino acids 5. fatty substances 6. other constitutes are available in the internal environment
difference between extracellular fluid and intracellular fluid
intracellular fluid contains large amounts of K+, Mg, P ions. extracellular fluid contains large amounts of Na, Cl, and bicarbonate ions(HCO3+) plus nutrients for cells like oxygen, glucose, fatty acids, and amino acids also contain CO2 transported from cells to lungs to be excreted, and cellular waste products transported to kidney’s
homeostasis
maintenance of nearly constant conditions in the internal environment
term homeostasis coined by
American physiologist Walter Cannon
how is homeostasis maintained
all organs and tissues of the body perform functions that help maintain these relatively constant conditions. normal body functions require intergrated actions of cells, tissues, organs, multiple nervous , hormonal, and local control systems to contribute to homeostasis.
examples of homeostasis
lungs provide O2 to extracellular fluid to replenish the O2 used by the cells, kidney’s maintain constant ion concentration, gastrointestinal system provides nutrients.
disease
considered to be a state of disrupted homeostasis. but even in the presence of a disease homeostatic mechanisms continue to operate and maintain Vital functions.
pathophysiology
a discipline that seeks to explain how the various physiological processes are altered in a disease or injury.
extracellular fluid transported through the body in two stages
1) movement in blood through blood vessels
2) movement of fluids between blood capillaries and the intercellular spaces between the tissue cells.
how many times blood flows through the entire circulatory system
an average of once each minute when the body is at rest, and as many as 6 times each minute when a person is extremely active.
walls of the capillaries
are permeable to most molecules in the plans of the blood, with the exception of plasma proteins which are too large.
process of diffusion is caused by
kinetic motion of the molecule in both the plasma and the interstitial fluid
how is the homogeneity of extracellular fluid maintained
the extracellular fluid in both the plasma and interstitial fluid as well as through capillary pores is continually being mixed. few cells located more than 50 Micro meter from a capillary ensure diffusion of almost any subs. thereby maintaining homogeneity
how homogeneity is maintained in blood circulatory system
by mixing of extracellular fluid between blood plasma and tissue fluid at the capillaries
nervous system composed of 3 major parts
sensory input portion
central nervous system (integrated portion)
sensory output portion
function of sensory receptors
detects the state of the body or the state of the surrounding.
CNS composed of
- brain
2. spinal cord
function of the brain
stores information, generates thoughts, creates ambition, and can determine the reactions of the body in response to various sensations
motor sensory portion
appropriate sensory signals are then sent to the motor sensory portion of the NS to carry out desires.
motor sensory portion has two systems
- somatic system ( voluntary movements)
2. autonomic system (involuntary movements)
autonomic system function
operates at the subconscious level and control functioning of internal organs including pumping activity of the heart, movement of the gastrointestinal tract, secretion by body’s glands.
what secrete hormones
there are 8 endocrine glands, serval organs and tissues that secrete chemical substance called hormones
function of hormones
transported throughout the body through the extracellular fluid to other others of the body to help regulate cellular functions.
function of thyroid hormone
increases the rate of any reactions in all of the cells thus helps to set the tempo of bodily activities.
function of insulin
controls glucose metabolism.
adrenocortical hormones function
controls sodium and potassium ions, and proteins metabolism.
parathyroid hormone function
controls bones calcium and phosphate .
why does the hormonal system complement the nervous system
the nervous system helps regulate muscular and secretory actives whereas the hormonal system regulates many metabolic activities.