Hormones

2. Hormones and Chemical
Control Systems
Chapter 10
Student : Amani Riyadh Ahmad Alsharidah
University number: 435203244
Zoo575
1436- 1437

3. Content
• Introduction.
• Hormone and type of hormone .
• Communication between cell .
• The endocrine system .
• control of water and osmatic balance .
• Control of ion balance and PH .
• Control of development and growth .
• Growth hormone .
• Control of metabolic rate , temperature and color .
• Hormones and other behaviors: aggression, territoriality, and
migration.
• Pheromones .

4. Introduction
• All multicellular organisms require coordinating systems to link
the activities of different kinds of cells. While the nervous system
uses primarily electrical signals to transmit coordinating
messages very quickly.
• the hormonal or endocrine system uses chemical messengers. A
hormone is essentially a blood-borne messenger, released from
one kind of cell and acting in a regulatory fashion on one or more
other types.

5. Hormone
Chemical substance , synthesized by a specific organ or tissue and
secreted into the blood stream , which it is carried to other specific
sites in the body , where it exerts its action .
Hormone function :
1. Control of rate of enzymatic reaction .
2.Transport of ion or molecules across cell membrance .
3. Gene expression and protein synthesis .

6. To keep balance in
the endocrine
system

7. Different type of
cell
communication

8. only endocrine and
neuroendocrine
mechanisms are
usually regarded as
“hormonal”.

9. Type of hormone
Chemically hormone divided into :
•Protein (e.g. insulin) and peptide hormone (e.g.
oxytocin) .
•Amino acid hormone( e.g.Thyroxine) .
•Steroid hormone(e.g. Cortisol) .

10. Difference
between
peptide
and steroid
hormone in
mechanism

11. Problems in studying animal hormones
• Studying a hormone’s activities used to be very difficult, partly because
most hormones are present in the blood at very low levels , and the normal
or functional concentration was hard to assess .
We can study animal hormone by :
• bioassay techniques, assessing the response of an isolated tissue, or the
response of a whole animal, to artificially high or low hormone levels.This
could be done
1. by ablation (removing or destroying the tissue that produces the
hormone).
2. by implantation of additional gland tissue (or injection of its products).
• Radio immune assays (RIAs, using monoclonal antibodies against the
hormone) and competitive binding assays.

12. The endocrine system of vertebrate

14. Hormone
Function

16. Control of water and osmotic balance
osmoregulation are under hormonal control, with various
possible effects:
•regulating permeability to particular ions or water.
• controlling the rate of transport of one or more ions, or
changing the direction of this transport .
• Most vertebrates require particularly constant body fluid
composition.

17. Aquatic animals: water and salt exchanges at
the skin and gill
Invertebrate
•Many invertebrates have hormones that are called either
diuretic hormones or antidiuretic hormones .
•In molluscs, an ADH has been described for the marine
sea slug , allowing rapid water uptake through the skin in
hyperosmotic media.

18. vertebrate
• In most aquatic vertebrate , important role in water balance is played
by prolactin,This hormone reduces the losses of sodium and water at
the gills and in the gut, with a minor effect on the kidneys.
• Adrenal cortex hormones also affect water balance, by altering
sodium uptake systems, but their effects are differently located
according to taxonomic status and environmental need.
Aquatic animals: water and salt exchanges at
the skin and gill

19. Terrestrial animals: water balance via the
excretory system
Vertebrae
• The most important antidiuretic for terrestrial
• The main physiological action of ADH :
1. facilitate water resorption from the collecting ducts (and the lower distal
tubules) of the kidney.
2. stimulates sodium resorption
3. transport of urea (via urea channels) from the lumen of the collecting
ducts to the interstitial fluid of the kidney.
4. vasoconstricting effects on blood vessels .

21. Control of ion balance and pH
• Water balance is associated with salt balance .
• aquatic species, gill regulation with corticosteroids and natriuretic
peptides being major control agents for sodium in fish .
• For terrestrial animals, sodium is mainly regulated by the degree of
its renal resorption, and controlled largely via aldosterone .

22. Calcium
• calcium plays important roles in stimulus–secretion coupling, in
excitability and muscle contraction, in cell adhesion, and in blood
clotting. Low blood calcium leads to tetany or uncontrolled spasms in
skeletal muscle.
1. In fish calcium regulation at the gills, the corpuscles of Stannius
secreting a hypocalcemic hormone that enhances calcium uptake at
the gills .
2.In most other vertebrates, Ca2+ is regulated at the gut, kidney, and
bone mainly by parathyroid hormone (PTH) from the parathyroid
gland. In mammals also calcitonin hormone .
3. metabolites of vitamin D (cholecalciferol) act as calcium-regulating
hormones in many vertebrates.

23. Calcium regulation in mammals

24. Control of development and growth
a - Development and metamorphosis
• All animals go through a process of development, largely controlled by growth
factors .
• animals also show metamorphosis during growth , depending on changes in
either habit or trophic relationships .
• aquatic invertebrates metamorphosis, allowing an alternation of pelagic larval
phases (feeding on plankton or on stored yolk) with sessile benthic filter-feeding
adults .
• flying insects mature phase is a reproductive and dispersive phase and less
mobile larvae are the feeding phase .
• vertebrates metamorphosis is rare, but amphibious anurans to cope with their
transition from aquatic herbivorous tadpole to terrestrial carnivorous frog or toad

25. Insect development and metamorphosis
• The insects are best studied because of
their strongly metamorphic life cycle with
a particularly drastic reorganization of the
body.

26. Vertebrate development and metamorphosis
• The principal factors controlling development and metamorphosis in
vertebrates are thyroxine (T4) and the more active tri-iodothyronine
(T3).
• Their effects include increased protein synthesis, and increased cellular
respiration. Intestinal glucose absorption rises, muscle cells increase
their glucose uptake, and fat cells undergo lipolysis so that fatty acids
increase in the blood.
• Other hormones regulate particular effects, for example cortisol, which
stimulates production of the surfactants that allow lung expansion at
birth.

27. Vertebrate development and metamorphosis
• Postnatal growth involves molting in many vertebrates .
• mammals shed skin layers continuously, many birds and mammals
have pronounced seasonal molts with change of form or color of
the skin and its insulating layers..
• There are also stimuli to epidermal growth from ACTH and
vasotocin in some frogs and toads.

29. Growth hormone
invertebrate
•Invertebrates have relatively few known control systems
for growth.
•Molluscs also have a GH affecting both the soft tissues and
also the shell via promotion of calcium transport into the
mantle epithelium .

30. Growth hormone
vertebrate

31. Control of metabolism, temperature, and color
a ,1 – metabolism ( invertebrate)
• Very little is known about metabolic hormones in the simplest
invertebrates .
• Bivalve molluscs have a metabolic neurohormone from the visceral
ganglia that increases storage of lipids, protein, and glycogen, and an
insulin-like hormone from the cerebral ganglia also promotes
glycogen storage .

32. a ,2 - control of metabolism in vertebrate
Several of the hormones have important metabolic effects in vertebrates:
• Catecholamines elicit glycogen breakdown, gluconeogenesis and
lipolysis.
• Thyroid hormones and growth hormone cause an increase in protein
synthesis, as well as raising blood glucose and lipid levels.
• The pancreatic sugar-regulating hormones, glucagon and insulin that
control blood glucose level .
• adrenal cortex hormones are also key players for longer term metabolic
regulation. Cortisol and other glucocorticoids, triggered by pituitary
ACTH .

33. B-Temperature control
• Hormones seem only rarely to have direct controlling effects on
animal temperature balance.
• many of them affect metabolic processes in ways that influence
body temperature.
• These effects inevitably differ between ectothermic and
endothermic animals.

34. B - 1 : Ectothermic animals: varying metabolic rates
and effects of color
• Metabolic rate in ectotherms is partly influenced by heart rate .
• Hormonal thermal effects may also occur in ectothermic vertebrates.
Leptins can elevateTb slightly in lizards, with increasing metabolic rates.
• Thyroid hormones may also act thermogenically in some lizards, and if
injected there are increases in oxygen consumption, activity levels, and
daily averageTb .

35. B - 1 : Ectothermic animals: varying metabolic
rates and effects of color
• In many invertebrates, and in some
reptiles and amphibians, hormones
affecting body color also contribute to
thermoregulation.
• Animals generally change color via
chromatophores, epidermal cells in which
the pigment can be either highly
dispersed or highly concentrated

36. B-2 :Endotherms and the maintenance of body
temperature
• Body temperature is regulated by the hypothalamus in vertebrates .
• hormones are important because of calorigenic effects, raising the
metabolic rate and the body temperature.
• The thyroid hormones effect is rising basal metabolic rate.

37. B-2 :Endotherms and the maintenance of body
temperature
• epinephrine from the adrenal medulla is thermogenic, giving a rapid
transient warm-up in response to stress.
• Insulin, glucagon and glucocorticoids also have some thermogenic
effect, the latter triggered by stress-related ACTH release.
• ACTH shows an interesting parallel with invertebrates, since it
produces skin-darkening effect in many birds and mammals.
• Ovarian progesterone has a slightTb elevating effect in mammals,
helpful in determining when ovulation occurs the fertile period.

38. Hormones and other behaviors: aggression,
territoriality, and migration
• Aggression between animals is not particularly widespread, sometimes
involving contests for access to food or homes, but commonest in relation
to the breeding season.
• males in particular are competing for access to mates, or more indirectly
are competing for territories to which mates may be attracted.
• the hormones involved in aggressive behaviors are to be linked to the sex
hormones.
• in mammals and birds, testosterone is the main controller of male
aggression.

39. Hormones and other behaviors: aggression,
territoriality, and migration
• female aggression in birds and mammals tends to be greatest when they
are sexually non receptive, and increasing estrogen and progesterone
levels make a female less aggressive and more receptive.
• Many insects and vertebrates also have hormonal control of migration
behaviors.

40. Pheromone
• A pheromone is a chemical an animal produces which changes the
behavior of another animal of the same species (animals include
insects).
• Some describe pheromones as behavior-altering agents.
• Pheromones, unlike most other hormones are ectohormones - they
act outside the body of the individual that is secreting them - they
impact a behavior on another individual.

41. Pheromones
• Pheromones can be secreted to trigger many types of behaviors,
including:
• Alarm
• To follow a food trail
• Sexual arousal
• To tell other female insects to lay their eggs elsewhere.
• To respect a territory
• To bond (mother-baby)

43. Reference
• Environmental Physiology of Animals , SECOND EDITION ,Pat Willmer and
other .
• Google picture .
• http://www.medicalnewstoday.com.