REGULATION
Control of living systems.
Living systems – open systems; their existence depends on flow of energy and substances between
organism and environment in both directions.
Appears at all levels of the system (from cell – to the whole organism).
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
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
PARAMETER REST EXERCISE INCREASE (x)
Cardiac output (l/min) 5-6 25 (35) 4-5
Heart reserve
Heart rate
(t/min)
70 210 (250-190)
depends on age
3
Frequency reserve
Stroke volume
(ml)
75 115 1,5
Volume reserve
Systolic BP
(mmHg)
120 ? Diastolic
BP
(mmHg)
70 ? Pulse
BP
(mmHg)
50 70-100 1,5-2
Mean BP
(mmHg)
- - small increase
Muscle perfusion
(ml/min/100g)
2-4 60-120 30
(10% MVmax)
PARAMETER REST EXERCISE INCREASE (x)
Minute ventilation (l/min) 6-12 90-120 15-20
Respiratory frequency (d/min) 12-16 40-60 4-5
Tidal volume (ml) 0,5-0,75 2 3-4
Blood flow (l/min) 5,5 20 – 35 4-6
O2 intake (ml/min) -VO2 250-300 3000 10-12
Total CO2 (ml/min) 200 8000 40
pO2 (Torr) 40 25
O2 extraction (%) + + ++
VESICULAR FOLLICLE
PRIMARY FOLLICLE - FSH
Growth acceleration of primary follicle – change into vesicular follicle:
1) estrogens released into follicle stimulate granul. cells
increased number of receptors for FSH – POSITIVE FEEDBACK
(higher sensitivity for FSH!!!)
2) Increased number of receptors for LH (estrogens and FSH) – another acceleration of growth due to „higher
sensitivity“ to LH
3) Increased estrogens and LH secretion accelerates growth of theca cells, secretion is increased
explosive growth of follicle
DOMINANT FOLLICLE
1. High level of estrogens from the fastest-growing follicle
2. Negative feedback on FSH production from adenohypophysis
3. Drop in FSH secretion
4. „Dominant follicle“ continues in growing due to intrinsic positive feedback
5. Other follicles grow slowly and subsequently become atretic
MECHANISM OF OVULATION
LH
PROGESTERON
Hyperaemia of follicle
Secretion of prostaglandins
Weakening of follicle wall
PROTEOLYTIC ENZYMES
(collagenases from theca externa)
Degeneration of stigma
Rupture of follicle
Release of oocyte
Transudation of plasma into follicle
Swallowing of follicle
FEELING OF HUNGER
LACK OF FOOD
Hungry
contractions of
stomach
Decreased
glucose
availability
Decreased heat
production
Changes of lipid
metabolism
Mechanoreceptors Glucoreceptors Internal termoreceptors
(hypothalamus)
„Liporeceptors“
HUNGER
SHORT-TERMED REGULATION
LONG-TERMED REGULATION
Compensation of dietary mistakes
FEELING OF SATIETY
FOOD INTAKE
Chewing
movements
Receptors in
nose, mouth,
oesophagus,
intestine
Mechanoreceptors of
stomach
GIT chemoreceptors
SATIETY
PRERESORPTIVE FEEDING
RESORPTIVE FEEDING
Central
gluco-
thermo-
lipo-
receptors
COMPILING THE INFORMATION IN CNS
(ventromedial hypothalamus)
HYPOTHESIS:
1. Lipostatic
2. H. of intestinal peptides
3. Glucostatic
4. Thermostatic
FOOD INTAKE REGULATION
ADIPOSE TISSUE
INCREASE OF BODY MASSLOSS OF BODY MASS
- LEPTIN +LEPTIN
HYPOTHALAMUS
HYPOTHALAMUS
NPY
RESPONSE TO FASTING
MSH
RESPONSE TO OBESITY
NPY RECEPTOR
MSH RECEPTOR
+ Food intake
- Reproduction
- Temperature
- Energy expenditure
- Food intake
+ Energy expenditurePARASYMPATHETIC
ACTIVITY SYMPATHETIC
ACTIVITY
MCH
OREXIN A, B
POMC derivatives