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.
what did the immune system consist of
White blood cells, tissues derived from WBC, lymph nodes, lymph vessels that Peggy the body from pathogens such as bacteria, viruses, parasites, and fungi.
mechanisms of the immune system
- Distinguishes between own cells and foreign substances and cells.
- and destroying them by phagocytosis, or by producing sensitised lymphocytes, or producing specialised proteins called antibodies that either destroy or neutralize the invader.
function of the integumentary system
- the skin and it’s other appendages ( hair, nails, glass and other structures) cover, cushion, and protect deeper tissue and internal organs of the body.
- boundary between the internal environment and outside world.
- temperature regulation.
- excretion of waste products.
- provide a density interface between the body and external environment.
what part of body weight does the skin comprise
12-15% of total body weight
why is reproduction considered as a homeostatic function
helps maintain homeostasis by generating new beings to take the place of those that are dying.
example of a control system
the genetic control system
genetic control system
operates in all cells to help control intracellular and extracellular functions
how organ systems operate
- within organs: controls functions of individual parts of the organ.
- throughout the entire body: to control the interrelations between the organs.
respiratory system operates in association with nervous system to
regulate the concentration of Carbon dioxide in extracellular fluid.
liver and pancreas regulate
concentration of glucose in extracellular fluid
kidney’s regulates
concentration of hydrogen, sodium, potassium, phosphate and other ions in the extracellular fluid.
the values outside the normal range of concentration of substances in the body are caused by
illness, injury or major environmental challenges.
the values outside the normal range of concentration of substances in the body are caused by
illness, injury or major environmental challenges.
normal value of oxygen
40mmHg
normal value of Carbon dioxide
45 mmHg
normal value of sodium ion
142 mmol/L
normal value of potassium ions
4.2 mmol/L
normal value of calcium
1.2 mmol/L
normal value of chloride
106 mmol/L
normal value of bicarbonate ion
24 mmol/L
normal value of glucose
90 mg/dL
normal value of temperature
98.4 F° (37 °C)
normal value of pH
7.4 pH
normal range of oxygen
35-45 mmHg
normal range of Carbon dioxide
35-45 mmHg
normal range of potassium
3.8- 5 mmol/L
normal range of sodium
138-146 mmol/L
normal range of calcium
1-1.4 mmol/L
normal range of chloride ion
103-112 mmol/L
normal range of bicarbonate ion
24-32 mmol/L
normal range of glucose
75-95 mg/dL
normal range of temperature
98-98.8 F° (37°C)
normal range of pH
7.3-7.5 pH
short-term non-lethal limit of oxygen
10-1000 mmHg
short-term non-lethal limit of carbon dioxide
5-80 mmHg
short-term non-lethal limit of sodium
115-175 mmol/L
short-term non-lethal limit of potassium
1.5-9.0 mmol/L
short-term non-lethal limit of calcium
0.5-2.0 mmol/L
short-term non-lethal limit of chloride
70-130 mmol/L
short-term non-lethal limit of bicarbonate ion
8-45 mmol/L
short-term non-lethal limit of glucose
20-1500 mg/dL
short-term non-lethal limit of temperature
65-110F° ( 18.3- 43.3 °C)
what happens when concentration of potassium becomes 1/3 of the normal value
person most likely becomes paralyzed as the result of inability of nerves to carry signals.
if the potassium concentration increase 2 or more times than the normal value
the person heart muscles are likely to get severely depressed.
when a persons calcium levels become 1/2 of the normal value
the person could get tetanic contraction in the muscles in the entire body due to the generation of spontaneous nerve impulses in the peripheral nerves
when glucose value reaches below 1/2 of the normal value
person exhibits extreme irritability and sometimes even convulsions
all homeostatic mechanisms have a certain mechanism in common
negative feedback
what is negative feedback
if a factor is excessive or deficient a control system initiates negative feedback which is a series of changes that returns the factor to its certain mean value this maintaining homeostasis.
what is gain
the degree of effectiveness with which a control system maintains constant conditions is determined by the gain of the negative feedback
how to calculate gain
gain= correction/error
negative feedback
when the initial stimulus is removed
positive feedback
when the Initial stimulus cause more and more of the same. it is also know as the vicious cycle. if the positive feedback is mild it can be overcome by negative feedback mechanism
when is positive feedback taken as advantageous
- blood clotting
- child birth
- generating nerve signals
how is clotting a advantageous positive feedback
when a blood vessel ruptures and fly behind to form and multiple enzymes called clotting factors get activated within the cloth and further activate inactivated enzymes of the adjacent blood to further increase clotting and finally plugs the vessel
how is childbirth an advantage of positive feedback
during child birth when the babys head begins to push through the cervix and stretch the cervical muscles sends a signal back to the uterus muscles to cause stronger ,contractions. these contractions push the baby through the cervix and cervical stretch cause more powerful contractions and so on until the baby is born
how is nerve impluse generation an advantage of positive feedback
when a neuron is stimulated a few Na ions leak from a channel and enter the interior of a nerve cell this cause it’s potentials to change leading to opening of more channels which leads to an explosion of ions into the cell which creates an action potential. which leads to a flow of electric current in side and outside the cell and this continues until the impluse reaches the end of the fibre
what is feed forward control
some movement of the body are so rapid there is no enough time for the nerve signal from the peripheral parts to travel to the brain and then back to periphery part . therefore the brain uses a principle called feed forward control to cause required muscle contraction. these signals apprise the brain whether the the movement is performed correctly. if not the correction is sent the next time the movement is required.
what is feed forward control
some movement of the body are so rapid there is no enough time for the nerve signal from the peripheral parts to travel to the brain and then back to periphery part . therefore the brain uses a principle called feed forward control to cause required muscle contraction. these signals apprise the brain whether the the movement is performed correctly. if not the correction is sent the next time the movement is required.
what is adaptive control
when feed forward control takes place the signal apprise the brain whether the movement is performed correctly and if not the brain corrects the feed-forward signals that it sends to the muscles the next time the movement is required and if still further correction is necessary this process will be performed for subsequent movements (delayed negative feedback)
cell membrane
lipid bilayer the envelopes the cell within which proteins are embedded also called “fluid mosaic model”
endoplasmic reticulum
a network of tubular and flat vesicular structures in the cytoplasm.
types of endoplasmic reticulum
- granular ER
2. agranular (smooth)ER
nucleus
control center of the cell containing DNA which are the genes that determines the characteristics of the proteins and also promotes cell reproduction
oxidative phosphorylation
it is the process by which ATP is synthesized in the mitochondria by respiratory enzymes
phagocytosis
is a form of endocytosis where in large particles are ingested such as bacteria, damaged tissue etc.
pinocytosis
is a form of endocytosis where in minute particles are ingested that form vesicles of extracellular fluid and particulates constituents inside the cell cytoplasm
