2. Hormones
Classifying Hormones by Structure
Steroid Hormones
Fat-soluble chemical messenger synthesized
from cholesterol
Examples: gonadal (sex) hormones, thyroid
Peptide Hormones
Chemical messenger synthesized by cellular
DNA that acts to affect the target cell’s
physiology
Examples: insulin, growth hormone
3. Hormones
Classifying Hormones by Function
Hormones that maintain homeostasis
State of internal metabolic balance and regulation of
physiological systems in an organism
Gonadal (sex) hormones
Control reproductive functions and sexual appearance
and identity
Stress hormones (e.g., glucocorticoids)
Secreted in times of stress (fight or flight); important in
protein and carbohydrate metabolism
7. Hormones
Homeostatic Hormones
Homeostasis of intracellular and extracellular
environments are essential to life
Diabetus mellitus
Caused by a failure of the pancreas to secrete
enough (or any) insulin
Hyperglycemia: High blood-glucose levels; cells
are not using glucose and therefore are not able to
function properly
Hypoglycemia: Low blood-glucose levels
8. Hormones
Gonadal Hormones
Sex hormones begin to affect us before we
are born and continue to affect us
throughout our life
Organizational Hypothesis
Proposal that actions of hormones during
development alter tissue differentiation
Example: Testosterone masculinizes the brain
9. Biological effects of sex hormones
organizational effects: permanent
structural changes elicited by sex
hormones during critical period of
embryonic / fetal life
activational effects: reversible effects of
sex hormones (e.g. estrus)
11. Hormones
Gonadal Hormones
Sex hormones contribute to brain differences:
Male brain is slightly larger than female after
correcting for body size
Right hemisphere is larger than the left hemisphere
in men
Female brains have higher rates of cerebral blood
flow and glucose utilization
Parts of the corpus callosum are larger in women
Language areas of the brain are somewhat larger in
women
13. Neural Control of Sexual Behavior
Brain Mechanisms
Sexually dimorphic nucleus (SDN):
A nucleus in the preoptic area that is much larger in males
than in females; first observed in rats; plays a role in male
sexual behavior.
Periaqueductal gray matter (PAG):
The region of the midbrain that surrounds the cerebral
aqueduct; plays an essential role in various species-typical
behaviors, including female sexual behavior.
15. Hormones
Gonadal Hormones
Sex hormones contribute to differences in
cognitive performance:
Men tend to excel on spatial tasks whereas women
tend to excel on verbal tasks
Performance of women differs during the course of
menstruation
Low female sex hormones: Better spatial performance
High female sex hormones: Better verbal performance
Differences between pre- and postmenopause, and
during various stages of pregnancy
16. Gender differences in brain
structure & function
less lateralization of cerebral hemispheres in women
(in men, left more concerned with verbal skills, right
with visual-spatial function)
larger fiber tracts in female corpus callosum
“sexually dimorphic nucleus” present in hypothalamus
(also: INAH 3)
Males > FemalesFemales > Males
17. Difference in Solving
Intellectual Problems
• Boys and girls
different way of
developing brains.
• Difference between
boys and girls lies in
patterns of ability
rather than in overall
level of intelligence
(IQ).
20. Hormonal Control of Sexual Behavior of
Laboratory Animals
Males
Oxytocin:
A hormone secreted by the posterior pituitary gland; causes
contraction of the smooth muscle of the milk ducts, the
uterus, and the male ejaculatory system.
Prolactin:
A hormone of the anterior pituitary gland, necessary for
production of milk; has an inhibitory effect on male sexual
behavior.
22. Hormonal Control of Sexual
Behavior
Hormonal Control of Female
Reproductive Cycles
Corpus luteum:
A cluster of cells that develops from
the ovarian follicle after ovulation;
secretes estradiol and progesterone.
Progesterone:
A steroid hormone produced by the
ovary that maintains the endometrial
lining of the uterus during the later part
of the menstrual cycle and during
pregnancy.
23. Organizational Effects of Androgens on
Behavior:
Masculinization and Defeminization
Effects of Pheromones
Pheromone:
A chemical released by one animal that affects the behavior
or physiology of another animal; usually smelled or tasted.
Lee-Boot effect:
The slowing and eventual cessation of estrous cycles in
groups of female animals that are housed together; caused
by a pheromone in the animals urine.
24. Organizational Effects of Androgens on
Behavior:
Masculinization and Defeminization
Effects of Pheromones
Whitten effect:
The synchronization of the menstrual or estrous cycle of a
group of females, which occurs only in the presence of a
pheromone in a male’s urine.
Vandenbergh effect:
The earlier onset of puberty seen in female animals that are
housed with males; caused by a pheromone in the male’s
urine.
25.
26. Hormones
Stress Hormones
Stressor
A stimulus that challenges the body’s
homeostasis and triggers arousal
Stress Response
The physiological and behavioral arousal and any
attempt to reduce the stress
Two sequences
Fast-acting: Activation of sympathetic nervous system;
“fight-or-flight” response
Slow-acting: Activation of parasympathetic nervous
system; “rest-and-digest” response
27. Stress Disorders
Stress:
A general, imprecise term that can refer either to a stress
response or to a stressor (stressful situation).
Stressor:
A stimulus (or situation) that produces a stress response.
28.
29. Stress Disorders
Fight-or-flight response:
A species-typical response preparatory to fighting or fleeing;
thought to be responsible for some of the deleterious effects
of stressful situations on health.
30. Stress Disorders
Physiology of Stress
Glucocorticoid:
One of a group of hormones of the adrenal cortex that are
important in protein and carbohydrate metabolism, secreted
especially in times of stress.
31. Stress Disorders
Physiology of Stress
Corticotropin-releasing hormone (CRH):
A hypothalamic hormone that stimulates the anterior
pituitary gland to secrete ACTH.
Adrenocorticotropic hormone (ACTH):
A hormone released by the anterior pituitary gland in
response to CRH; stimulates the adrenal cortex to produce
glucocorticoids.
50. Stress and Depression Hypothesis
After depression treatment Cort
secretion returns to normal
Cushing Disease- always
depressed
High CORT and CRH disregulates
5ht, causing Learned Helplessness
Symptomology matches CRH
functions
Dexamethasone Test
51. Stress and Depression Hypothesis
CRH/Depression leads to behavioral
symptoms and inability to learn new
coping strategies
Therapy or SSRI Drug treatment allows
for the brake to become functional again
Prozac—BDNF ---ROS-neurogenesis
Therapeutic lag = Mrna CORT rebalancing
53. Stress Disorders
Psychoneuroimmunology
Psychoneuroimmunology:
The branch of neuroscience involved with interactions
between environmental stimuli, the nervous system, and the
immune system.
Antigen:
A protein present on a microorganism that permits the
immune system to recognize the microorganism as an
invader.
54. Stress Disorders
Psychoneuroimmunology
Antibody:
A protein produced by a cell of the immune system that
recognizes antigens present on invading microorganisms.
B-lymphocyte:
A white blood cell that originates in the bone marrow; part of
the immune system.
55. Stress Disorders
Psychoneuroimmunology
Immunoglobulin:
An antibody released by B-lymphocytes that bind with
antigens and help to destroy invading microorganisms.
T-lymphocytes:
A white blood cell that originates in the thymus gland; part of
the immune system.
56. Stress Disorders
Psychoneuroimmunology
Cytokine:
A category of chemicals released by certain white blood
cells when they detect the presence of an invading
microorganism; causes other white blood cells to proliferate
and mount an attack against the invader.
57. Hormones
Ending a Stress Response
Normally, stress responses are brief
Stress responses are turned on and off in
the brain
Sapolsky (2003)
Hippocampus is involved in turning off the stress
response
Too much cortisol will damage neurons in the
hippocampus
Vicious cycle involving prolonged stress, cortisol
levels, and hippocampal functioning
58. Hormones
Ending a Stress Response
Posttraumatic Stress Disorder
Syndrome characterized by physiological
arousal symptoms related to recurring memories
and dreams related to a traumatic event – for
months or years after the event
Editor's Notes
M Women and men differ not only in physical attributes and reproductive function but also in the way in which they solve intellectual problems. It is cool to say that men and women are equally potential regardless of the type of the tasks, but it is not true. Let’s see how different they are.
The authors suggest that the magnitude of stress responses to emotional arousing events affect the storage of emotional memories. Norepinephrine and Cort released in response to emotional provoking stimuli modulate the output of the amygdala There are a lot of data to support this theory: The amygdala has a very high density of adrenoceptor Levels of Norepinephrine in the amygdala go up as footshock intensity goes up Drugs that increase Cort or Norepinephrine in the hippocampus and amygdala enhance memory. Drugs that block Norepinephrine in the amygdala ( muscimol) impair memory So McGaugh feels that the sympathetic nervous system is responsible for memory consolation of fearful memories.
