REGULATION
Control of living systems.
Living systems – open systems; their existence depends
on flow of energy, substrates and signaling molecules
between organism and environment in both directions.
Appears on all levels of system (cell – whole organism).
Regulation nervous vs. Regulation humoral.
BASIC TYPES OF FEEDBACK
SERIAL
PARALLEL
NEGATIVE DIRECT NEGATIVE INDIRECT
FEEDBACK
NEGATIVE
POSITIVE
Deviation oscillates or continuously increases.
POSITIVE FEEDBACK
PHYSIOLOGICAL
Ensuring of systems, activation
PATHOLOGICAL
Instability - death
NEGATIVE FEEDBACK
• plays a role in regulations
• compensates the difference of regulated parameter
• minimizes the difference between real values of regulated
parameter and so-called desired value
Regulated
system
Regulator
Input
value
of regulator
Regulatory deviation
Regulated
parameter
Desired value
POSITIVE FEEDBACK
• No regulatory effect
• It does not compensate the deviation, but amplifies it
PHYSIOLOGY OF ADAPTATION
Adaptation or Environmental Physiology
It examines the influence of environment on living systems
and their ability to adapt to changed conditions
REACTION (sec, min) vs. ADAPTATION (min, hours, days)
REACTION (REGULATION): direct, immediate response of
organism on environmental changes
ADAPTATION = a complex of biochemical, functional and
structural changes in organism caused by long-lasting and
repeated environmental changes
ADAPTATION
INDIVIDUAL
GENETICALLY FIXED
MECHANISMS OF ADAPTATION
= processes which lead to new, functionally better
parameters.
Aim is to reach new, more advantageous qualities for
surviving of the individual or species.
DURATION OF ADAPTATION:
Minutes - years
CONFORMATION ADAPTATION
Organisms are forced to create new total level of
parameters
REGULATORY ADAPTATION
Operation range of function is changed
MECHANISMS OF ADAPTATION
1. Changed plasticity of nervous system
• changes at molecular level in CNS
• gene expression changes
• regulation of number of neurites
• changes in neuronal nets (cortical fields)
2) Changes in organ size (adaptation to exercise)
3) Changes of autonomous tonus (athletes)
4) Temporary changes of skin colour (sunbathing)
CLASSIFICATION OF ADAPTATIONS
a) According to target parameter
• To cold
• To heat
• To dietary changes
• To high altitude
• To changed air composition
• To physical exercise ……….
b) According to output
•Adaptations at the level of five basic senses
•Adaptation changes of behavior
ACCLIMATION
Reaction of whole organism on change in one changed factor
in environment
ACCLIMATISATION
Reaction of whole organism on change in several changed
factors in environment
CIVILISATION DISEASES = MALADAPTATIONS
•Gastric ulcer disease
•Hypertension
•CAD
•Psychoses
STUDYING OF ADAPTATION animal models
human volunteers
ADAPTATION TO COLD
1. PROTECTION FROM HEAT LOSS ( feather,
vasoconstriction, increased amount of adipose tissue under the
skin)
2. INCREASE OF HEAT PRODUCTION ( higher metabolic
exchange)
3. DOWNWARDS SHIFT OF SET-POINT ( opposite to fever,
behaviour as in hibernating animals )
18th century: surviving of sailors in cold water
1887: V. Priesnitz, S. Kneipp
People suffer from low temperatures less in winter than in summer.
ADAPTATION INSULATIVE
METABOLIC
HYPOTHERMIC
Acclimation.
Human: as tropical animals
Seal, fog, seagull: arctic animals (thermoneutral zone
between 20 – 40°C, thermoregulating below 20°C)
In humans always all three mechanisms activated at the
same time.
In adapted – O2 consumption decreases, HR not changed,
BP increases (by 20 – 40mmHg), feeling of discomfort is
lower (starts at lower temperature), downward shift of setpoint
(by 0.75°C)
ADAPTATION PROCESS
- Mainly new value of set-point
- Changed diet (higher energy consumption, but NO
increase of body mass, slowly increases body fat
percentage)
- Cold diuresis (excretion of Na+ and K+) – up to 60x,
mediated by ANF, haemoconcentration, increased number
of leucocytes and erythrocytes
- Glycaemia changes: in non-adapted people decreases
(stress), in adapted - increases (no stress)
- Decrease of threshold for pain on skin ( total habituation
– decreased sensitivity of receptors); stress analgesia in the
course of adaptation
- Decrease of threshold for muscle shivering
ADAPTATION TO HEAT
1) SWEAT PRODUCTION may be doubled
2) THREASHOLD FOR SWEATING decreases to lower
temperatures (both core and periphery)
3) DECREASED CONTENT OF ELECTROLYTES IN
SWEAT
4) FEELING OF THIRST increases
5) HIDROMEIOSIS (decreased production of sweat in
humid hot clima, after the period of profuse sweating;
decreases idle dropping of sweat)
6) ADAPTATION OF TOLERANCE TO HEAT in
inhabitants in the tropics, threshold for sweating is
increased to higher body temperatures.
ATTENTION must be paid to physical exercise !!!
HIGH ALTITUDE ADAPTATION
CARDIOVASCULAR RESPONSE: tachycardia and
increased cardiac output at rest, more pronounced during
exercise (BP increases during exercise only slightly)
RESPIRATORY RESPONSE: increased minute
ventilation, more pronounced during exercise
ACID-BASE BALANCE: respiratory alkalosis (RQ> 1)
O2 TRANSPORTATION: shift of dissociation curve to left
FAST RESPONSE (reaction) (hours)
HIGH ALTITUDE ACCLIMATISATION
It takes at least several weeks, fully developed after months or
years.
CARDIOVASCULAR RESPONSE: HR and CO are
normalized, pulmonary arterioles constrict – pulmonary
hypertension
RESPIRATORY RESPONSE: minute ventilation is stabilized
(directly proportional to high altitude hypoxia), central
chemoreceptors adapt
INCREASED RELEASE OF ERYTHROPOETIN:
polyglobulia, transport capacity of blood for O2 increases,
viscosity of blood increases, density of mitochondria increases,
myoglobin content increases
ACCLIMATISATION RECOMMENDATION:
After 3 days: A-B balance is restored, Hb concentration increases
After several weeks: it is possible to exercise
GENETIC ADAPTATION IN ALPINE TRIBES:
• Bigger chest
• Higher density of capillary net in lungs
• Bigger heart (EDV)
• Higher CO
• Higher Hb concentration
• Bigger bone marrow
PATHOLOGICAL REATIONS TO HIGH ALTITUDE:
• Mountain disease (above 3 th. m.a.s.)
• Mountain disorientation (disorder - above 5 th. m.a.s.)
• Mountain edema
Adaptation from birth ???
ADAPTATION TO EXERCISE
1. Muscle hypertrophy
2. Athlete‘s heart
Athlete‘s heart :
•Hypertrophy dilatation
•Increased volume reserve (1.5x)
•Increased chronotropic reserve
„Physiological“ hypertrophy
•Prolongation of muscle fibres and increase of their thickness
(NOT their number!!!)
•Accompanied by normal or increased contractility (speed of ATP
hydrolysis by myosin and maximal speed of muscle shortening are
either normal or increased)
•In muscles: increased number of mitochondria, increased activity
of oxidative metabolism enzymes, proliferation of capillaries
Transversal heart section:
hypertonic heart with concentric hypertrophy (left)
normal heart (middle)
hypertonic heart with eccentric hypertrophy = hypertrophy + dilation (right)