Exam 3 Flashcards
Zygote
A fertilized egg
46 diploid chromosomes, 23 haploid from each parent
0-5/6 days
Gamete
Sex cells/egg or sperm cells
The only haploid cells in the body are gamete cells
Sex of fetus is determined by…
The arrangement of sex hormones (XX or XY)
Asexual reproduction
Does not involve the fusion of gametes
Produce genetically identical offspring
Evolve slowly and adapt poorly
Sexual reproduction
Produce offspring with reconstituted genome (re-assortment of chromosomes)
Survival advantage because they evolve quicker and adapt better, and harmful recessive mutations are masked by a normal gene
New genomes produced by crossing over of genetic material
Law of independent assortment
The allele a gamete receives for one gene does not influence the allele received for another gene
How do hormones produce functional sex organs?
Peptide–moves into brain and stimulates changes in order to modulate sexual feedback and genitalia
Steroid–allows for movement in and out of BBB (communication between body and CNS restricted by hydrophobic BBB
Hypothalamus
Control of hormone secretion
Anterior pituitary
Stimulated by hypothalamus
Hormone secretion by the thyroid, adrenal cortex, and gonads
Growth
Posterior pituitary
Stimulated by hypothalamus
Water and salt balance
Endocrinology
The study of hormones
Neuroendocrine interactions
Endocrine system glands secrete chemicals/hormones into the bloodstream, travel to target tissues, produce long-lasting responses over time, influence metabolism and development, pass through BBB
Nervous system cells travel to target tissues via electrical current, produce fast responses, influence acute changes in body systems
Neuroendocrine cells
Neurons that communicate with hormones in conjunction with neurochemicals
Hormone chemicals
Produced and released from differentiated cell types to affect other cells in the body and brain
Interactions occur through blood circulation to target
Endocrine system cells release hormones that travel long distances through the bloodstream
Depending on chemical composition effects are fast (adrenaline) or slow (steroids)
HPG axis
Hypothalamic-pituitary-gonadal axis
Regulates reproductive activity and the release of ovarian hormones in animals and humans
Menstrual cycle
Menstrual phase (1-5) –> pre-ovulatory phase (1-14) –> ovulation (14th day) –> post-ovulatory phase (14 days after)
Follicular phase –> ovulation –> luteal phase
Hormone regulation in the HPG axis in females
Hypothalamus sends GnRH to anterior pituitary –> anterior pituitary produces FSH and LH –> FSH and LH rise and help to mature the primary and secondary follicles (which happens over menstruation) –> once follicles are mature, they release estrogen which goes back to the hypothalamus and tells it to stop producing FSH and LH (acting as a negative feedback inhibitor)
Hormone regulation in the HPG axis in males
Hypothalamus sends GnRH to anterior pituitary –> anterior pituitary produces LH and FSH –> LH and FSH act on the testes to produce testosterone –> testosterone goes back to the hypothalamus to inhibit GnRH
Cholesterol
Template for all steroid hormones
Can be used to create progesterone (female reproduction), estradiol (female reproduction), and testosterone (male reproduction)
Hormones released from the anterior pituitary gland
GnRH, TRH, PRH, GHRH, CRH, SRIH
Act on the pituitary gland
GnRH
Gonadotropin-releasing hormone
Releases LH and FSH (depending on frequency of stimulation); targets the reproductive system
Stimulates production of sex hormones by gonads (LH) and the production of sperm and eggs (FSH)
TRH
Thyroid-releasing hormone
Releases thyroid-stimulating hormone and stimulates prolactin secretion
Acts on thyroid gland
Regulates metabolism
PRH
Prolactin-releasing hormone
Releases prolactin
Acts on mammary glands
Promotes milk production
GHRH
Growth hormone-releasing hormone
Releases growth hormone; acts on liver, bone, and muscle
Induces targets to produce insulin-like growth factors that stimulate body growth and a higher metabolic rate
CRH
Corticotropin-releasing hormone
Releases adrenocorticotropic hormone (ACTH)
Acts on adrenal glands
Induces targets to produce glucocorticoids, which regulate metabolism and the stress response
SRIH
Somatotropin release inhibiting hormone
Inhibits growth hormone
Hormones stored by the posterior pituitary gland
ADH and oxytocin; produced by the hypothalamus
ADH
Antidiuretic hormone
Acts on kidneys, sweat glands, and circulatory system
Water balance
Oxytocin
Acts on female reproductive system
Triggers uterine contractions during childbirth
HPA axis
Hypothalamic pituitary adrenal axis
Hypothalamus sends CRH to anterior pituitary which releases ACTH –> ACTH acts on adrenal gland to produce cortisol –> cortisol provides feedback to the pituitary and hypothalamus to stop producing CRH
Stress activates HPA axis (chronic stress results in negative feedback at all levels)
Psychopharmacology
Classification of drugs based upon general type of CNS effect produced
Depressants
Produce general decrease in cognitive and behavioral processes
Alcohol (ETOH), marijuana, barbiturates (sedatives), benzodiazepines (tranquilizers)
Stimulants
Produce general increase in behavior and thought
Nicotine, caffeine, amphetamine, and cocaine
Act on dopamine
Hallucinogens and opiates
Alter perception of reality
LSD and derivatives, opium
Act on serotonin
Tolerance
More and more of the drug is required to produce desired effect–leads to addiction
Addiction
Physiological and psychological need for a drug
Withdrawal
Physical and psychological symptoms opposite from those the drug induces
Opponent-process theory
A drug produces changes from homeostasis (A-process), and the body tries to reduce changes by producing opposite effects (B-process)
Tolerance is an increased strength of the B-process
Addiction is the need for more A-process to counteract the negative B-process
Withdrawal is the removal of the A-process leaving behind a strengthened B-process
Alcohol and marijuana
Depressant
Administration–beverage/inhalant
Distribution–small, intense (rapid absorption)
Elimination–metabolized by the liver
CNS effects–visual impairment, lack of motor coordination, increased reaction time, euphoria, and release from inhibitions
Sedatives/Tranquilizers
Depressant
Act to decrease anxiety via global depression of the CNS, effects are supra additive
Barbiturates
Class of synthetic compounds, usually taken orally and distributed through the bloodstream
Act as GABA agonist on GABA receptors (increases effect of GABA)
Currently used as sleep aids and anticonvulsants
Risks include addiction, tolerance, and insomnia upon withdrawal
Benzodiazepines
Tranquilizer
Synthetic compound used extensively as antianxiety drugs
Taken orally and distributed through the bloodstream
GABA agonist
Common side effects–lethargy and drowsiness
Risks include addiction, tolerance, and withdrawal, also great hazard for overdose especially if mixed with alcohol
Cocaine
Stimulant
Administration–nasally, crack (highly pure form) can be smokes
Distribution–absorbed by mucosal membranes (nasal) or absorbed directly into the blood (inhaled)
Elimination–metabolized by esterase enzyme in the brain
CNS effects–increased heart rate, blood pressure, and body temperature, feelings of euphoria
Risks include addiction, tolerance, and withdrawal
Long-term health risks–cardiovascular or cerebrovascular problems
Amphetamines
Stimulant
Synthetic compound with chemical structure similar to catecholamines
Severe abuse potential
Administration–oral, nasal, IV
Distribution–via bloodstream
Elimination–metabolized by liver
CNS effects–increase in blood pressure, motor activity, libido, and pain threshold, decreases in bronchial muscle tone, fatigue, appetite, and euphoria, high doses result in paranoia
Risks include addiction, tolerance, and withdrawal
Ecstacy
Hallucinogen
Synthetic of mescaline
Dangerous and potent toxin of serotonin cells; ability to super stimulate serotonin in the brain, causing cell death
Little risk of addiction, tolerance, and withdrawal
LSD
Hallucinogen
Acts as a serotonin agonist at inhibitory autoreceptors (inhibit inhibiting neurons, get excitation)
Orally as blots or sugar cubes
Effects include increased heart rate and blood pressure, pupil dilation, perceptual alteration, occasionally psychotic episodes and synesthesia
Tolerance does develop, but not addiction
Pharmacokinetics
How drugs move through the body; administration –> distribution –> elimination
Drug half-life
Amount of time required for removal of 50% of drug in blood
First order transformation
Drug clearance rate proceeds exponentially
Converting enzymes > drug to transform
Zero order transformation
Drug clearance rate is fixed
Drug to transform > converting enzymes
Concentration of drug saturates metabolizing enzymes
Schizophrenia
Group of disorders, including 6-month period of disturbances of communication, perception, and thought processes
Chlorpromazine (sedative) reduces florid symptoms
Schizophrenia key distinctions
Not a mood/affective disorder because people aren’t perceiving something incorrectly, they’re perceiving something that isn’t there
Models of schizophrenia
Inability to segregate relevant vs. irrelevant sensory stimulation and/or memories
Sensory abnormality producing “false” realities
Hallucinations (auditory)
Florid schizophrenia symptoms
Type 1/positive
Presence of distinctive behaviors (disorganized thinking, paranoia, delusions of grandeur, bizarre ideation)
Negative schizophrenia symptoms
Type 2
Absence of normal and social behavior (neglect of personal hygiene, odd behavior and ideas, social isolation, withdrawal, catatonia)
Often precede florid symptoms
Rule of thirds
After onset of schizophrenia, 1/3 spontaneously recover, 1/3 spontaneous remission and relapse (controlled by medication), 1/3 chronically ill
Affective Illness
Person perceives reality (sensory stimuli) normally, but feeling about that reality may be distorted
Mania
A period of abnormally elevated, extreme changes in mood or emotions, energy level, or activity level
Effectively treated by lithium
Often relapses and leads to periods of depression
Mania symptoms
Accelerated thought process, euphoria, exaggerated sexual or physical appetite, illusions of invincibility, grandiose ambitions
Depression symptoms
Suicidal thoughts, anhedonia (lack of pleasure), psychomotor retardation, expressions of helplessness, hopelessness, and worthlessness, and sleep disturbances resulting in lost REM sleep
Unipolar illness
Periods of depression alternate with normal periods
Bipolar illness
Brief periods of mania oscillate with brief periods of depression and prolonged periods of normalcy
Effectively managed with lithium during manic state and antidepressants during depressive state
SSRIs
Selective serotonin reuptake inhibitors
Raise extracellular levels of serotonin –> when serotonin is being passed between pre- and post- synaptic cells, there’s excess in the synapse and whatever isn’t used is discarded or reused; SSRIs stop serotonin being reused and makes sure it stays in the synapse a bit longer so serotonin’s effects are amplified
Prozac (fluoxetine), Zoloft (sertraline), and Paxil (paroxetine)
Therapeutic effects take weeks even though biochemical effects are immediate
