Physiology: Homeostasis Flashcards
Internal environment
ECF
Mileu interior
ECF
__% of the human body is body fluid
60%
two major compartments where total body water is distributed
intracellular fluid (ICF) and extracellular fluid (ECF)
___ of the fluid is inside cells (intracellular fluid)
2/3
___ of fluid is found in spaces outside the cells (extracellular fluid)
1/3
Percentage of ECF composition
80% interstitial fluid 20% blood plasma
surround the cells and makes up ¾ of the ECF volume
Interstitial fluids
blood plasma is contained in what compartment
ECF: intravascular
accumulation of fluid in the peritoneal cavity of individuals with liver disease
ascites
Who first articulated the ECF as the internal environments
Claude Bernard, a French physiologist
“The environment within”
Mileu interior/ECF/Internal environment
He recognized that the organ systems of the body are designed and functioned to maintain a constant milieu interior (“constant internal environment”
Claude Bernard
T/F, All cells live in the same environment (ECF)
True
T/F, inorder for cell to function, it requires the proper concentration of oxygen, glucose, ions, amino acids, fatty substances and other constituents available in its internal environment (ECF)
true
ECF/ ICF, Contains large amounts of sodium, chloride and bicarbonate ions
ECF
ECF/ ICF, contains Large amounts of potassium, magnesium and phosphate ions
ICF
ECF/ ICF, contains Nutrients for cells (oxygen, glucose, fatty acids, amino acids)
ECF
ECF/ICF, transports Carbon dioxide and other waste products (kidneys and lungs)
ECF
Maintenance of nearly constant conditions in the internal environment
Homeostasis
The tendency of our body to achieve a relatively stable equilibrium between interdependent elements
Homeostasis
provide oxygen to the extracellular fluid in order to replenish the oxygen that are used by the cells
Lungs
responsible for maintaining constant ion concentration
Kidneys
contribute to homeostasis by providing nutrients so that when cells use up the nutrients that are found in the ECF they will now be replenished from the nutrients that have been absorbed by the gastrointestinal tract
GI tract
T/F, Each organ system will have a role in the maintenance of homeostasis
True
T/F, different organ systems will work together in order to return your body to the steady state in case there is a stimulus that disrupts this balance
True
Detects change that causes imbalance to the homeostasis
receptor
Pathway where receptor sends signal toward control center
afferent pathway
process the information that has been sent and give a command
Control center of the nervous system
Pathway where control center send the command towards effector
efferent pathway
Aim of the command/response sent by the NS to the effector cell
reduce the effect of the disrupting stimulus in order to return your body to the homeostatic level or to the balanced level
Describe general process when a state of imbalance occurs
- Stimulus produces change in variable 2. Receptor detects changes 3. Input: Information sent along afferent pathway to control center 4. Output: Information sent along efferent pathway to effector 5. Reduce effect of stimulus and return body to balance level
2 Stages in ECF Transport
- Movement of blood through the body in the blood vessels 2. Movement of fluids between the blood capillaries and the intracellular spaces between the tissue cells
the smallest blood vessel, they are the ones that would be located closest to the cells and also to the intercellular spaces
Capillaries
T/F, continual exchange of extracellular fluid occurring between the blood plasma and the interstitial space will happen as blood pass thru capillaries
true
T/F, The walls of these capillaries are permeable to most molecules
true
T/F, The molecules can go in and out of these capillaries because of their size
false, permeability
The process of diffusion is going to be caused by?
Kinetic motion of molecules
refers to the state where in fluid and dissolved molecules are continuously moving and bouncing in all directions within the plasma and the fluid in the interstitial space and the capillary space
Kinetic motion
ensures the diffusion of substances from the capillary to the cell within a few seconds
distance of capillary to cell
T/F, both that of plasma and that of the interstitial fluid is continuously being mixed hence they appear homogenous
true
sources of nutrients and substances necessary for the functioning?
o Respiratory system o Gastrointestinal tract o Liver and other metabolic organs o Musculoskeletal system
The function of respiratory system will be in coordination with what system
circulatory system
The final destination of oxygen in the respiratory tract
alveoli
Oxygenated blood is found in?
arteries
unoxygenated blood is found in?
veins
T/F, Each time blood passes through the body, it also flows through the lungs
True
organ that changes the composition of absorbed substances into more usable forms
Liver
They help modify the absorbed substances or store them until needed
Liver, Fat cells, GI mucosa, kidneys and endocrine glands
Provide motility for protection against adverse surroundings and obtain food & nutrients
Musculoskeletal System
Systems responsible for REMOVAL OF METABOLIC WASTE PRODUCT
Lungs Kidneys GI Liver
T/F, removal of carbon dioxide occurs at the same time blood picks up oxygen in the lungs, carbon dioxide is released from the blood into the lung alveoli
true
Part of kidney responsible for the reabsorption of Glucose, Amino acids, water and ions
Renal tubule
End product of poorly absorbed substance in the kidney
Urea
A consequences due to the accumulation of metabolic waste products
Disease states
It secretes many of these wastes into the bile and eventually in the feces
Liver
Organs responsible for the removal of waste products in the body
Lung, Kidney, GI tract, Liver
Main systems that regulate body functions
Nervous system, Hormonal system, Reproductive system
3 major part of the nervous system
Sensory input CNS Motor output
detect state of the body and surroundings
Sensory input
Is where sensory input is integrated for processing
CNS
Part of CNS where it store information, generate thoughts, determine reactions
Brain and Spinal cord
Part of NS in which command is carried out
Motor output
It operates subconsciously and controls functions of many internal organs
ANS
important in generating new beings to help take place those that are dying
Reproductive system
regulates metabolic function and complements the nervous system
Hormonal system
Hormone that control glucose metabolism
Insulin
Hormone that control sodium ion, potassium ion, and protein metabolism
adrenocortical hormone
Hormone that increase rate of chemical reactions in the cell & metabolic functions (act on other organs)
Thyroid hormone
Hormone that act on bone to control calcium and phosphate levels; control calcium reabsorption in bone
Parathyroid hormone
It stimulates hormones (TSH > controls thyroid gland)
Pituitary gland
The most intricate control system that would operate in all cells to help control intracellular and extracellular functions.
genetic control system
operates in association with nervous system in order to control the carbon dioxide concentration in the extracellular fluid
Respiratory system
They coordinate to regulate concentration of glucose in ECF
Liver and pancreas
regulate the concentration of different ions and substances like hydrogen, sodium, potassium, phosphate and other ions in ECF
Kidneys
T/F, The mechanism of oxygen buffering actually depends on the chemical characteristic of hemoglobin.
True
T/F, if there is already too much oxygen that is present, hemoglobin having strong affinity to oxygen would not immediately release oxygen in tissues
true
T/F, if oxygen concentration in the tissue fluid is too high then it would release sufficient oxygen levels
false, it will not release
major product of oxidative reaction of cells
Carbon dioxide
T/F, Higher than normal carbon dioxide concentration excites the respiratory center.
true
T/F, Elevated carbon dioxide concentration is very dangerous because it can stop the production of energy in the body
true
T/F, Hyperventilation is a consequence of elevated CO2 in the blood
true
Stretch receptors
Baroreceptors
How baroreceptor works when BP is elevated?
arterial pressure rises too high, baroreceptors will send nerve impulses to medulla of brain, decreasing the impulses that would be sent from medulla to the blood vessel causing relaxation of blood vessel and a decrease in blood pressure.
How baroreceptor works when BP is too low?
Stretch receptors relaxes, allowing vasomotor center to become more active than usual. This causes vasoconstriction and increased heart pumping.
Site of the vasomotor center
Medulla
Normal value for Oxygen
40 (35-45) mmhg
Normal value for CO2
40 (35-45) mmhg
Normal value for Sodium ion
142 (138-146) mmhg
Normal value for Potassium ion
4.2 (3.8-5.0)
Normal value for calcium ion
102 (1.0-1.4)
Normal value for chloride ion
106 (103-112)mmhg
Normal value for Bicarbonate ion
24 (24-32)
Normal value for glucose
90 (75-95)
Normal body temperature
37C/98.4F (98-98.8 F)
Normal acid base balance
7.4 (7.37.5)
increase in body temperature more than 11F or 7C, will lead to ?
vicious cycle of increasing cellular metabolism that can destroy the cell
very high potassium levels can cause
abnormality in cardiac contraction
very low potassium concentration can cause
paralysis as a result of inability of nerves to carry signals.
fall to more than half of the normal level of calcium could cause
tetanic contraction of the muscles
less than half concentration of glucose could cause
mental irritability and sometimes convulsions
Cycle in which the output of a system “feed backs” or communicates back to either modify or reinforce the action taken by the system
FEEDBACK MECHANISMS
The single objective of feedback mechanism is
maintaining balance or homeostasis
FEEDBACK MECHANISMS may operate at what levels
o Tissue level o Organ level o System level o Body level, integrating other organ systems
Components of Feedback System
o Sensor or receptor o Integrator o Effector
detects specific changes in the environment
Sensor or receptor
act to direct impulses to the place where response can be made
Integrator
performs the appropriate response
Effector
Mechanism that maintains a factor at some mean value
NEGATIVE FEEDBACK
Reverse a change and Restore abnormal values to normal
NEGATIVE FEEDBACK
How negative feedback system works?
Stimulus->imbalance –>Detected by receptor/sensor–>Input set via afferent pathway–>Control center–>output sent via efferent pathway–>effector–>response–>return to balance
Examples of Negative feedback system
o Regulation of CO2 concentration o Blood Pressure Regulation Through Negative Feedback Mechanism o Thyroid Hormone Regulation Through Negative Feedback Mechanism o Thermoregulation
The major mechanisms of compensation in shock is
NEGATIVE FEEDBACK
Signs and symptoms of shock include
systolic blood pressure less than 90 mmHg; hypotension; rapid resting heart rate; weak rapid pulse; clammy, cool, pale skin; sweating; altered mental state; decreased urinary output; thirst; and acidosis
Explain how Thyroid Hormone Regulation Through Negative Feedback Mechanism
The thyrotropin releasing hormone (TRH) –>stimulate anterior pituitary gland–>thyroid stimulating hormone (TSH) –>stimulate the gland to secrete thyroid hormones. High levels of T; negative feedback –>anterior pituitary & hypothalamus–>decrease the levels of released TRH –>decrease the levels of the TSH–>decrease the levels of thyroid hormones.
Hypothyroidism: ___TSH
High
Hyperthyroidism: ___TSH
Low
T/F, In hypothyroid patient, hypothalamus is stimulated to release TRH; there is increased TSH to try to compensate for low thyroid hormones
True
T/F, In hyperthyroid patient, negative feedback will be sent to decrease TRH and TSH
True
Receptors in thermoregulation
Thermoreceptor in skin and hypothalamus
Integrators in thermoregulation
Control centers (preoptic area and heat promoting center in hypothalamus, and hypothalamic neurosecretory cells)
Effectors in thermoregulation
Vasoconstriction, increased cellular metabolism, shivering, increased metabolic rate
What is stimulated in the anterior pituitary gland to release TSH?
Thyrotrophs
How vasoconstrictions works in thermoregulation?
decreases flow of warm blood, and thus transfer of heat from the internal organs to the skin;
stimulated release of ___ and _____ increases cellular metabolism which increases heat production;
epinephrine and norepinephrine
repetitive muscle contraction that produce heat
shivering
increased levels of _____ slowly increase metabolic rate which then rises the body temperature.
thyroid hormones
Strengthens or reinforces a change and Produces a “vicious cycle”
Positive Feedback
T/F, A mild degree of positive feedback can be overcome by the negative feedback control mechanisms of the body
true
T/F, positive feedback may promote instability leading to development of diseases
true
Example of positive feedback in the body
Action potential Blood clot formation Parturition Release of calcium Sexual arousal LH surge
How AP works in positive feedback
Membrane of a nerve fiber is stimulated–>Leakage of sodium ions through sodium channels–>Sodium in the interior of the nerve fiber–>Change in membrane potential–>Opening of more channels–>Sodium entering cells–>Creates nerve action potential–>Flow of electrical currents–>Further initiates additional action potential
How blood clot formation works in positive feedback
Rupture of blood clot–>Formation of primary plug–>Activation of clotting factors–>Secondary plug formation
Why is blood clot formation needs to be regulated?
Pathological blood clot –> thrombus –> causes Myocardial infarction/Heart Attack
How Parturition works in positive feedback
Uterine contractions become strong enough–> stretch of cervix send signals through uterine muscles back to the body of uterus –>more powerful contractions If powerful enough= baby will be born; if not=will stop and repeat
What is the positive feedback of estrogen on the anterior pituitary?
surge of luteinizing hormone (LH) just before ovulation
Degree of effectiveness with which a control system maintains constant conditions is determined by ?
gain of negative feedback.
Interconnected control mechanisms
Adaptive Control
Types of adaptive control
o Simple feedback systems o Complex feedback systems
Mechanism is used when movements of the body occur so rapidly that there is not enough time for nerve signals to travel from the peripheral parts of the body all the way to the brain and then back to the periphery again to control the movement
FEED-FORWARD CONTROL
Process of FEED-FORWARD CONTROL
Sensory nerve signals from moving parts of the periphery appraise the brain if movement is done correctly Sends corrected signals on the next movement If further correction is need, done on the next movement.
T/F, adaptive control occurs in Delayed negative feedback
true
Negative vs Positive feedback
Computation for gain
