Endocrinology & Reproduction Flashcards
Where are endocrine glands found?
Scattered around the body
What do endocrine glands secrete?
Hormones
Once hormones are secreted, where do they want to go?
Target cells
How do hormones reach their target cells?
Bloodstream
What do target cells have to recognize specific hormones?
Receptors
How does a target cell recognize a hormone?
Through hormone-receptor binding
What do target cells do?
Regulate or direct a particular bodily function
What is the length of response produced by the endocrine system?
Long
How are the 2 hormone categories determined?
Based on solubility
What are the 2 categories of hormones?
1) Hydrophilic
2) Lipophilic
What is special about hydrophilic hormones?
They can be dissolved in plasma
What are 2 examples of hydrophilic hormones?
Peptide hormones (insulin and growth hormone) and Catecholamines
What is special about lipophilic hormones?
They can pass through membranes and do not dissolve in plasma
What are 2 examples of lipophilic hormones?
Steroid hormones and Thyroid hormone
What 3 things does the endocrine system regulate?
1) Organic metabolism
2) Water and electrolyte balance
3) RBC production and use
How does the endocrine system help the body cope?
By inducing adaptive change during stressful situations
What does the endocrine system promote?
Smooth, sequential growth and development
What is the function of the endocrine system that involves the ANS?
Control and integration of circulation as well as digestion and absorption of food
What do tropic hormones do?
Regulate hormone secretion of another endocrine gland
Does one gland produce only one hormone?
No, one gland can produce multiple hormones
Does one hormone get secreted by only one gland?
No, more than one gland can produce and secrete the same hormone
Does one hormone have only one type of target cell?
No, one hormone can have more than one type of target cell
What about secretion varies?
Rate
Is one target cell influenced by only one hormone?
No, a single target cell can be influenced by more than one hormone
What can a chemical messenger be?
A hormone or neurotransmitter
Do all endocrine organs only have endocrine functions?
No, many endocrine organs have other functions that are not endocrine (ex: ovaries)
What are 3 methods to control plasma concentration of a hormone?
1) Regulate changes in rate of hormone secretion
2) Increase rate of removal from blood by metabolic inactivation or excretion
3) Increase rate of activation or binding of hormone to plasma proteins
What 2 direct regulatory inputs influence secretory output of endocrine cells?
- Neural input
- Input from another hormone
When does negative feedback control exist?
When output of a system counteracts a change in input
What does negative feedback control do to plasma concentration of a hormone?
Maintains the concentration at a given level or set-point
What is the purpose of neuroendocrine reflexes?
To produce a sudden increase in hormone secretion in response to a specific stimulus
What is an example of a neuroendocrine reflex?
Increased secretion of cortisol by the adrenal cortex during a stress response
What do endocrine disorders most commonly result from?
Inappropriate rates of secretion causing abnormal plasma concentrations of a hormone
What is hyposecretion?
Too little hormone is secreted
What kind of glands does the endocrine system consist of?
Ductless endocrine glands
What is hypersecretion?
Too much hormone is secreted
What is primary hyposecretion?
Too little hormone secretion due to abnormality within gland
What are 5 causes of primary hyposecretion?
Genetic, Dietary, Chemical or toxic, Immunologic, and Cancer
What is secondary hyposecretion?
Gland is normal but decreased hormone secretion due to deficiency of the glands tropic hormone
What are 2 causes of hypersecretion?
Tumours that ignore normal regulatory input and continuously secrete excess hormone, and Immunologic
What is primary hypersecretion?
Too much hormone secretion due to abnormality within gland
What is secondary hypersecretion?
Excessive stimulation from outside the gland causes oversecretion
What are the 3 ways in which hormones can influence the activity of other hormones at target cells?
1) Permissiveness
2) Synergism
3) Antagonism
What is permissiveness?
One hormone must present in adequate amounts for full exertion of another hormones effect
What is synergism?
When actions of several hormones are complimentary and the combined effect is greater than the sum of their separate effects
What is antagonism?
When one hormone causes loss of another hormones receptors causing reduced effectiveness of the second hormone
What does cholesterol act as a precursor for?
Lipophilic steroid hormones
How do hydrophilic hormones produce effects?
Bind to surface membrane receptors and produce effects through a second-messenger system
How do lipophilic hormones produce effects?
Bind to intracellular receptors and produce effects through changes in gene expression
What do hormone-receptor complexes recognize?
Specific sequences in DNA called Hormone-Response-Element (HRE)
What are 2 differences between the nervous system and endocrine system?
1) Length of response (NS = short, brief and precise; ES = long)
2) Target tissues (NS = muscles and glands; ES = every tissue in the body)
Location: hypothalamus
In the superior brainstem below thalamus
Location: pituitary gland
Inferior to hypothalamus
What does antidiuretic mean?
Produce less urine and store more water
What is the function of ADH?
Conserve body water and regulate osmotic pressure of body fluids
How is ADH secretion triggered?
By osmoreceptors in the brain from an increase in osmolarity due to dehydration
What does ADH act on and how?
Kidney cells (distal convolute tubule and medullary collecting ducts) via cell surface receptors and cAMP formation
What does ADH do to kidney cells?
Enhances water permeability and reabsorption
What is the function of oxytocin?
Stimulates contraction of smooth muscle cells
What does oxytocin act on?
Mammary gland and uterus
What stimulates oxytocin release?
Suckling and childbirth
What does oxytocin release stimulate?
1) Contraction of myoepithelial cells in breast to expel milk
2) Rhythmic uterine contractions
What is a clinical use of oxytocin?
1) To induce labour
2) Therapeutically postpartum to decrease bleeding
What does an ADH deficiency mean?
Inability to retain water
What are symptoms of ADH deficiency?
Excess thirst and frequent urination
What are 2 treatments for ADH deficiency and what do they do?
1) Clofibrate to increase ADH secretion
2) Chlorpropamide to increase kidney response to ADH
What does ADH excess mean?
Excess water retention
What are symptoms of excess ADH?
Headache, drowsiness, and nausea
What are 2 treatments for excess ADH and what do they do?
1) Butorphanol to decrease ADH secretion
2) Demechlocycline to decrease kidney response to ADH
What are the 6 hypothalamic hormones in the regulation of anterior pituitary hormones?
Corticotropin-releasing hormone (CRH); Thyrotropin-release hormone (TRH); Gonadotropin-releasing hormone (GnRH); Growth hormone-releasing hormone (GHRH); Somatostatin; Dopamine
What effect does corticotropin-releasing hormone have on anterior pituitary hormones?
Increases ACTH
What effect does thyrotropin-releasing hormone have on anterior pituitary hormones?
Increase TSH and prolactin
What effect does gonadotropin-releasing hormone have on anterior pituitary hormones?
Increases LH/FSH
What effect does growth hormone-releasing hormone have on anterior pituitary hormones?
Increases growth hormone
What effect does somatostatin have on anterior pituitary hormones?
Decreases growth hormone
What effect does dopamine have on anterior pituitary hormones?
Decreases prolactin
What effect does tropic hormone have on the hypothalamus?
Negative
What effect does tropic hormone have on the anterior pituitary?
Negative and positive
What effect does pituitary hormone have on the hypothalamus?
Negative
What does the hypothalamus secrete to the anterior pituitary?
Releasing/inhibitory factor
What does the anterior pituitary secrete to the endocrine gland?
Pituitary hormone
What does the endocrine gland secrete to the target tissue?
Tropic hormone
What kind of pattern do hypothalamic and pituitary hormones have and why?
Pulsatile/rhythmic secretion pattern due to fluctuation of neuronal activity
What is the clinical relevance of the secretion pattern for hypothalamic and pituitary hormones?
1) Maintains target organ sensitivity
2) If the pulsatile secretion was to be abolished, hormone secretion would be diminished
What is the source of growth hormone?
Somatotropes and somatommammotropes of anterior pituitary
What are the 5 actions of growth hormone?
Decrease insulin sensitivity; Increase lipolysis; Increase IGF-1; Increase protein synthesis; Increase epiphyseal (bone) growth
What are 2 actions of IGF-1?
Increase protein synthesis and increase bone growth
What stimulates growth hormone release?
GHRH, hypoglycemia, exercise, some amino acids, and sleep
What inhibits growth hormone release?
Somatostatin, negative feedback of IGF-1, and hyperglycemia
What is the source of prolactin?
Lactotropes and somatommammotropes of anterior pituitary
What are 3 actions of prolactin?
1) Promote growth and function of mammary glands to aid in milk production
2) Increase maternal behaviour
3) When [prolactin] is very high, inhibits gonadotropin secretion which decreases steroidogenesis
What stimulates prolactin release?
Oxytocin, TRH, VIP, and estrogen
What inhibits prolactin?
Dopamine
What can cause growth hormone excess?
Somatotropin tumor
What can occur from growth hormone excess?
1) Gigantism if occurs early in life
2) Acromegaly if occurs after body growth has stopped
What is acromegaly?
Excess soft tissue hyperplasia
What are 3 treatments for growth hormone excess?
1) Tumor removal
2) SS analogs
3) GH receptor antagonist (blocker)
What can cause growth hormone deficiency?
Hypothalamic or pituitary lesions
What can occur from growth hormone deficiency?
1) Proportional short-stature if occurs early in life
2) Adult hypopituitarism
What are symptoms of adult hypopituitarism?
Weakness; Fine wrinkling and pale skin; Loss of sex drive; Genital atrophy; Menstrual cycle cessation
What are 2 other causes of retarded growth in which growth hormone is not deficient?
1) GH receptor defect in target tissues
2) IGF-1 deficiency
What can treat growth hormone deficiency?
GH and IGF-1 replacement
What are 3 causes of prolactin excess?
1) Hyperprolactinemia
2) Dopamine receptor blockers
3) Stress, high amount of physical activity, underweight
What is hyperprolactinemia?
Most common form of pituitary hyperfunction caused by adenomas of lactotropes
What can cause the blockage of dopamine receptors?
Some psychiatric medications
What are the consequences of prolactin excess in females?
Anti-gonadal action which causes secondary amenorrhea, leading to infertility and galactorrhea
What is secondary amenorrhea?
Cessation of menstrual cycle
What is galactorrhea?
Inappropriate milk production
What are the consequences of prolactin excess for males?
Impotence, decreased sperm count and infertility
What is a treatment option for excess prolactin?
Dopamine agonists (such as Cabergoline or Parlodel) suppress prolactin secretion and shrink prolactinomas
True or false: deficiency of prolactin is rare?
True
What does pituitary ACTH regulate?
The adrenal gland
What 3 things does pituitary ACTH indirectly affect?
1) Melanin synthesis
2) Immune response
3) Decrease food intake
What are the 3 sections that the adrenal gland is divided into (from outermost to innermost)?
1) Zona glomerulosa
2) Zona fasciculata
3) Zona reticularis
Where does the mineralocorticoid pathway take place?
Zona glomerulosa
Where does the glucocorticoid pathway take place?
Zona fasciculata
Where does the androgen pathway take place?
Zona reticularis
What is the major form of glucocorticoid?
Cortisol
What is cortisol bound to and where?
Transcortin in circulation
Why is cortisol essential for life?
Its important direct effects on intermediary metabolism of carbs, proteins, and lipids
What are 4 functions of cortisol?
1) Stimulates protein breakdown to amino acids
2) Facilitates lipid breakdown in adipose tissue to fatty acids and glycerol
3) Promotes hepatic gluconeogenesis from amino acids, glycerol, and fatty acids
4) Makes glucose available to brain by inhibiting utilization by other tissues
At what level do anti-inflammatory and immunosuppressive effects of glucocorticoids occur?
Pharmacological levels of glucocorticoids
What are 3 anti-inflammatory effects of glucocorticoids?
1) Inhibit local reaction to injury
2) Reduce local release of degradative enzymes
3) Decrease fibroblast proliferation and collagen deposition
What are 3 examples of anti-inflammatory events that need glucocorticoids?
1) Rheumatoid arthritis
2) Trauma
3) Insect bites
What are 3 immunosuppressive effects of glucocorticoids?
1) Inhibit IL-1 production by macrophages, resulting in decreased T cell recruitment
2) Inhibit IL-2 production from T Helper cells, thus reducing T and B cell formation
3) Induce death of T cells
What are 2 examples of immunosuppressive events that need glucocorticoids?
1) Prevent organ/graft rejection
2) Manage allergic disorders
What should be considered for a patient on long-term use of glucocorticoids?
Impaired body’s defense against infections; Loss of bone mass; Atrophy of adrenal gland; Other metabolic effects (such as hyperglycemia)
What is DHEA the main source of?
Angroden in females
What does aldosterone affect?
Kidney to regulate water and salt metabolism
What is the function of cortisol?
Increase metabolic fuels, such as blood glucose, amino acids, and fatty acids
What do glucocoorticoids exert strong negative feedback on?
Hypothalamus and anterior pituitary
Why does atrophy of anterior pituitary corticotropes occur in the pituitary-adreanl axis by glucocorticoids?
Because no ACTH is required
Why does atrophy of adrenal cortex occur in the pituitary-adreanl axis by glucocorticoids?
Lack of stimulation by ACTH
What is the major form of mineralocorticoids in the adrenal?
Aldosterone
What is the function of aldosterone?
Control body fluid volume by increasing sodium reabsorption by kidneys
What stimulates aldosterone secretion? (2)
Activation of RAAS in response to decreased blood pressure, low plasma sodium, and high plasma potassium; and ACTH
What is a major form of adrenal androgens?
DHEA (dehydroepiandrosterone)
Is DHEA a strong or weak androgen?
Weak
What is DHEA important for in males?
Nothing
What is DHEA important for in females?
Enhancement of pubertal growth spurt; Maintains secondary sex characteristics; Sexual desire; Some conversion to estrogen by aromatase in peripheral tissues
What are conditions of aldosterone excess?
Primary hyperaldosteronism (Conn’s syndrome) and Secondary hyperaldosteronism
What are causes of aldosterone excess?
Hypersecreting tumour of zona glomerulosa or High renin-angiotensin
What are symptoms of aldosterone excess?
Increased sodium (hypernatremia); Decreased potassium (hypokalemia); Hypertension
What is a condition of cortisol excess?
Cushing’s syndrome
What are causes of cortisol excess?
Excess CRH/ACTH; Adrenal tumour; Ectopic ACTH (lung cancer)
What are symptoms of cortisol excess? (5)
1) Hyperglycemia
2) Excess protein breakdown
3) Abnormal fat distribution
4) Insulin resistance
5) Decreased immune and inflammatory response
What is a condition of androgen excess?
Congential Adrenal Hyperplasia (CAH) / Androgenita Syndrome in females
What is a cause of androgen excess?
Genetic deficiency in cortisol synthetic enzymes (21- and 11-OH)
What are symptoms of androgen excess?
Inappropriate masculinization; Pseudohermaphroditism; Virilization in female; Pseudopuberty in boys
What occurs to ACTH in CAH and what does this cause?
Absence of negative feedback on ACTH; Causes increased ACTH, leading to increased DHEA, which produces a negative feedback on anterior pituitary which decreases production of LH/FSH, resulting in gonads not developing
What is a condition of cortisol and aldosterone deficiency?
Primary adrenal insufficiency (Addison’s Disease)
What is the cause of cortisol and aldosterone deficiency?
Destruction or atrophy of adrenal cortex
What are symptoms of cortisol deficiency?
Poor response to stress; Hypoglycemia; Low metabolic activites
What are symptoms of aldosterone deficiency?
Increased potassium (hyperkalemia) resulting in arrhythmia, decreased heart rate, and weakness; Decreased sodium (hyponatremia) resulting in edema, headache, confusion, muscle cramp, and weakness; Hypotension
What is a condition of cortisol deficiency?
Secondary adrenal insufficiency
What is a cause of cortisol deficiency?
Insufficient ACTH caused by hypothalamic or pituitary failure
What are adrenal medulla catecholamines composed of?
Modified postganglionic neurons without axons
What do the cell bodies of adrenal medulla catecholamines produce?
Epinephrine and some norepinephrine
What are 3 “rules” of the actions of adrenal catecholamines?
1) Effects in target organs are mediated by alpha and beta adrenergic receptors
2) Actions of one hormone by the two classes of receptors often produce opposite effects
3) When exerted through the same type of receptor, epinephrine and norepinephrine exert similar effects
Is gluconeogenesis alpha or beta mediated?
Alpha
Is arteriolar constriction alpha or beta mediated?
Alpha
Is muscle contraction alpha or beta mediated?
Alpha
Is decreased insulin secretion alpha or beta mediated?
Alpha
Is increased growth hormone secretion alpha or beta mediated?
Alpha
Is sweating alpha or beta mediated?
Alpha
Is dilation of pupils alpha or beta mediated?
Alpha
Is glycogenolysis alpha or beta mediated?
Beta
Is lipolysis and ketosis alpha or beta mediated?
Beta
Is decreased glucose utilization alpha or beta mediated?
Beta
Is arteriolar dilation alpha or beta mediated?
Beta
Is increased cardiac contractility alpha or beta mediated?
Beta (beta 1)
Is increased heart rate alpha or beta mediated?
Beta
Is muscle relaxation alpha or beta mediated?
Beta
Is increased insulin secretion alpha or beta mediated?
Beta
Is increased renin secretion alpha or beta mediated?
Beta
Is increased thyroid hormone secretion alpha or beta mediated?
Beta
What is pheochromocytoma?
Tumors arising from chromaffin cells in the SNS, mostly in the adrenal
What do pheochromocytoma tumors release?
Large quantities of epinephrine and/or norepinephrine and sometimes dopamine
What are the consequences of pheochromocytoma?
Hypertension; Increased heart rate (palpitations); Hyperglycemia; Anxiety; Headache; Weight loss; Sweating
What are treatment options for pheochromocytoma?
Surgery or Alpha and beta receptor blockers
What is stress?
A generalized, nonspecific response of the body to any factor that overwhelms the body’s compensatory abilities to maintain a state of homeostasis
What do stressors stimulate?
Cortisol release
What does the thyroid gland consist of?
2 lobes of endocrine tissue joined in the middle by isthmus (narrow portion of gland)
How are follicular cells arranged in the thyroid?
Into hollow spheres
What do follicular cells form?
A follicle
What is the lumen of follicular cells filled with?
Colloid
What is the function of colloid?
Serves as an extracellular storage site for thyroid hormone
What hormones do follicular cells produce in the thyroid?
1) T4/thyroxine
2) T3
- Iodine-containing and derived from tyrosine
What is the function of C cells in the thyroid?
Secrete peptide hormone calcitonin
What is the major function of the thyroid?
Synthesis, storage, and secretion of thyroid hormone
What are the 2 basic ingredients of thyroid hormone and how are they obtained by the body?
1) Tyrosine (synthesized by body)
2) Iodine (obtained from dietary intake)
Where does the synthesis of thyroid hormone occur?
On thyroglobulin molecules within colloid
How does synthesis of thyroid hormone occur?
1) Thyroglobulin is exported from follicular cells into colloid by exocytosis
2) Thyroid captures iodine from blood and transfers it into colloid by iodine pump
3) Within colloid, iodine attaches to tyrosine
4) Coupling process occurs between iodinated tyrosine molecules to form thyroid hormones
Where is thyroid hormone stored and for how long?
Stored in colloid until they are split off and secreted
How does secretion of thyroid hormone occur?
1) Follicular cells phagocytize thyroglobulin colloid
2) T3 and T4 are free to diffuse across plasma membrane and into blood
3) Most produced is T4 converted to T
What are 5 functions of thyroid hormone?
1) Determines basal metabolic rate
2) Influences synthesis and degradation of carbs, fat, and protein
3) Increases target-cell responsiveness to catecholamines
4) Increase heart rate
5) Aids in development of nervous system
What regulates the hypothalamus-pituitary-thyroid axis?
A negative-feedback system between hypothalamic TTRH, anterior pituitary TSH, and T3 and T4
What are causes of hypothyroidism?
1) Primary failure of thyroid gland
2) Secondary to deficinecy of TRH and/or TSH
3) Inadequate dietary supply of iodine
What causes cretinism?
Hypothyroidism from birth
What is myxedema?
Hypothyroidism is adults
What is treatment for hypothyroidism?
Replacement therapy (increase dietary iodine)
What is the most common cause of hyperthyroidism?
Graves’ disease
What is Graves’ disease?
An autoimmune disease in which the body incorrectly produces thyroid-stimulating immunoglobulins (TSI)
What is a physical characteristic of Graves’ disease?
Exopthalmos (bulging eyes)
What are some treatments for hyperthyroidism?
Surgical removal of a portion of the over-secreting thyroid; administration of radioactive iodine; antithyroid drugs
What is a goitre?
Swelling of the neck caused by enlarged thyroid
Why does plasma calcium have to be closely regulated?
To prevent changes in neuromuscular excitability
What 5 activities does calcium play a vital role in?
1) Excitation-contraction coupling in cardiac and smooth muscle
2) Stimulus-secretion coupling
3) Maintenance of tight junctions between cells
4) Clotting of blood
5) Bone formation
What does hypercalcemia result in?
Reduced excitability
What does hypocalcemia result in?
Overexcitability of nerves and muscles
What can severe overexcitability cause?
Fatal spastic contractions of respiratory muscles
What 3 hormones regulate plasma concentration of calcium?
1) Parathyroid hormone (PTH)
2) Calcitonin
3) Vitamin D
What gland secretes parathyroid hormone?
Parathyroid gland
What is parathyroid hormone the primary regulator of?
Calcium
What does parathyroid do to plasma concentration of calcium and how?
Raises free plasma calcium levels by its effects on bone, kidneys, and intestines
Why is parathyroid hormone essential for like?
It prevents fatal consequences of hypocalcemia
Parathyroid facilitates activation of ______
Vitamin D
When is calcitonin secreted?
In response to an increase in plasma calcium concentration
How does calcitonin work on calcium?
Lowers plasma calciu levels by inhibiting activity of bone osteoclasts
When is calcitonin important?
During hypercalcemia
What is the function of vitamin D?
Stimulates calcium and phosphate absorption from intestine
How can vitamin D be made by the body?
Can be synthesized from cholesterol derivative when exposed to sunlight
Describe the process of activating vitamin D
Must be activated first by liver and then by kidneys before it can exert its effect on intestines
What are symptoms of PTH hypersecretion?
Hypercalcemia and hypophosphatemia
What are symptoms of PTH hyposecretion?
Hypocalcemia and hyperphosphatemia
What is rickets?
Vitamin D deficiency in children
What is osteomalacia?
Vitamin D deficiency in adults
What does insulin do to blood glucose?
Decreases it
What does glucagon do to blood glucose?
Increases it
What does cortisol do to blood glucose?
Increases it
What does epinephrine do to blood glucose?
Increases it
What does growth hormone do to blood glucose?
Increases it
What are the endocrine cells of the pancreas?
Islets of Langerhans
What are the exocrine cells of the pancreas?
Acini
What are the 4 major cell types of the pancreas?
Alpha, beta, delta, and F
What hormone do alpha cells of the pancreas secrete?
Glucagon
What hormone do beta cells of the pancreas secrete?
Insulin
What hormone do delta cells of the pancreas secrete?
Somatostatin
What hormone do F cells of the pancreas secrete?
Pancreatic polypeptide
What connects the A and B chains of insulin?
2 disulphide covalent bonds between cysteine residues
What is the function of proinsulin?
Nothing
What is the function of the C peptide of insulin?
Unknown
What cleaves the A from C chains and B from C chains in insulin?
Proprotein convertase
What are 4 stimulants of insulin release?
1) Sugars (glucose, mannose)
2) Amino acids (leucine)
3) Vagus nerve stimulation
4) Sulfonylureas
What are 3 amplifiers of glucose-induced insulin release?
1) Enteric hormones
2) Neural amplifiers (beta-adrenergic effect of catecholamines)
3) Amino acids (arginine)
What are 2 inhibitors of insulin release?
1) Neural (alpha-adrenergic effect of catecholamines)
2) Humoral (somatostatin)
What happens to glucose, glucagon, and insulin levels as you eat?
Glucose levels rise quickly; insulin levels rise extremely fast; glucagon levels decrease gradually
What 4 processes does insulin promote?
1) Glucose uptake into cells
2) Glycogen synthesis
3) Lipid synthesis
4) Protein synthesis by increasing amino acid uptake
Insulin is _____
Anabolic
Where is glucagon produced?
In Islets of Langerhans by alpha cells
What are 3 functions of glucagon?
1) Releases glucose
2) Stimulates gluconeogenesis (production of glucose from non-glucose sources)
3) Stimulates lipolysis
Glycogen breakdown to glucose in muscles is unaffected by _____, but affected by ______
Glucagon; glucocorticoids
What happens to lactate produced by muscles?
It goes to liver to be converted to glucose
What are 3 functions of glucagon with respect to lipid metabolism?
1) Increase lipolysis
2) Increase glycerol utilization
3) Decrease triglyceride synthesis
What is diabetes mellitus?
A syndrome of disordered metabolism with hyperglycemia caused by a deficiency of insulin and/or a reduction in effectiveness of insulin
What are the 2 major forms of diabetes and what occurs in each type?
1) Type 1 – destruction of beta cells
2) Type 2 – reduced sensitivity to insulin
What are characteristics of type 2 diabetes?
Hyperglycemia and hyperinsulinemia
What are 4 common chronic complications of diabetes mellitus?
1) Ophthalmologic
2) Renal
3) Neurological
4) Cardiovascular
What is a treatment for type 1 diabetes?
Insulin
What are treatments for type 2 diabetes?
Nutritional therapy (exercise, balanced diet) and pharmacological therapy
What are some types of pharmacological therapy for type 2 diabetes?
1) Biguanides (hypoglycemic agents that inhibit gluconeogenesis)
2) Sulfonylureas (promotes insulin secretion)
3) Thiazolidinediones (increase sensitivity to insulin)
4) Glucosidase inhibitors (inhibit digestion of complex carbs therefore reducing sugar availability)
What are the male and female reproductive systems designed for?
To enable union of genetic material
What are primary reproductive organs?
Gonads; testes in male and ovaries in female
What are 2 functions of mature gonads?
1) Produce gametes (sperm in male and ova in female)
2) Secrete sex hormones (testosterone in males and estrogen and progesterone in females)
What is the reproductive tract?
System of specialized ducts that transport or house gametes after they are produced
What do accessory sex glands do?
Empty supportive secretions into reproductive tract
What is an example of a female accessory sex organ?
Breasts
What are external genitalia?
Externally visible portions of reproductive system
What are secondary sexual characteristics?
External characteristics not directly involved in reproduction that distinguish males and females typically after puberty
What are examples of secondary sexual characteristics?
Body configuration and hair distribution
What are 2 functions of the male reproductive tract?
1) Produce sperm
2) Deliver sperm to female
What are the organs of the male reproductive tract?
1) Testes
2) Penis
3) Accessory sex glands
What are testes and where are they found?
Sperm-producing organs suspended outside abdomen in skin-covered sac (scrotum)
What is the function of the penis?
Deposit sperm in female
What are examples of male accessory sex glands?
Seminal vesicles, prostate gland, bulbourethral glands
What is the function of male accessory sex glands?
Secrete substances that provide bulk of semen
What is the pathway of the male reproductive tract?
Epididymis, ductus deferens, ejaculatory duct, urethra
What are 6 functions of the female reproductive tract?
1) Cyclical production of ova
2) Reception of sperm
3) Transport of sperm and ovum to common site for union
4) Maintenance of developing fetus until it can survive in outside world
5) Giving birth
6) Nourishing infant after birth with milk
What is the product of fertilization?
Embryo
When does a embryo become a fetus?
After first 2 months of intrauterine development
What are the organs of the female reproductive tract?
1) Oviducts
2) Uterus
3) Vagina
4) Vulva
What are 2 functions of oviducts?
1) Pick up ova on ovulation
2) Site of fertilization
What 2 things is the uterus responsible for?
1) Maintenance of fetus during development
2) Expelling fetus at end of pregnancy
What does the vagina connect?
Uterus to external environment
What is the lower portion of the vagina?
Cervix
Location: vaginal opening
Perineal region between urethral opening and anal opening
What are the labia minora and labia majora?
Skin folds that surround vaginal and urethral openings
What is the vulva?
Collective term for female external genitalia
How many chromosomes do somatic cells contain?
46
How many chromosomes do gametes contain?
23
How is gametogenesis accomplished?
Meiosis
How many pairs of autosomes do we have?
22
How many pairs of sex chromosomes do we have?
1
What are the 3 levels of sexual differentiation?
1) Genetic
2) Gonadal
3) Phenotypic
What is genetic sexual differentiation?
The combination of sex chromosomes at time of conception (either 2 X’s or 1 X and 1 Y)
What is gonadal sexual differentiation?
Whether testes or ovaries develop
What determines gonadal sexual differentiation?
Presence or absence of Y chromosome
What is phenotypic sexual differentiation?
Apparent anatomic sex of individual
What determines phenotypic sexual differentiation?
Gonadal sex
What is a similarity between male and female external genitalia?
They develop from the same embryonic tissue
What does the undifferentiated external genitals in both sexes consist of?
A genital tubercle, paired urethral folds surrounding a urethral groove, and genital (labioscrotal) swellings
Which ducts degenerate in a female?
Wolffian ducts, leaving Mullerian ducts
Which ducts degenerate in a male?
Mullerian ducts, leaving Wolffian ducts
Why are testes found in the scrotum?
This location provides a cooler environment essential for spermaogenesis
Where is testosterone produced?
In Leydig cells of the testes that lie in connective tissue between seminiferous tubules
What does spermatogenesis begin with?
A spermatogonium
What is the final product of spermatogenesis?
Many spermatozoa
What are the 4 parts of a spermatozoan?
1) Head that contains the nucleus
2) Acrozome that caps the tip of the head; used to penetrate ovum
3) Midpiece which contains mitochondria
4) Tail which provides motility
What are 6 functions of Sertoli cell in the seminiferous tubules?
1) Form blood-testes barrier
2) Provide nourishment
3) Phagocytic
4) Secrete seminiferous tubule fluid which flushes released sperm from tubule into epididymis for storage and additional processing
5) Secrete androgen-binding protein
6) Site of action to control spermatogenesis
What are 3 functions of the epididymis and ductus deferens?
1) Store and concentrate sperm
2) Increase sperm motility and fertility prior to ejaculation
3) Mix sperm with secretions from accessory glands during ejaculation
What does the seminal vesicle contribute to semen?
Fructose for energy and prostaglandins
What does the prostate gland contribute to semen?
Alkaline fluid that neutralizes acidic vaginal secretions as well as clotting enzymes and fibrinolysin
What do bulbourethral glands contribute to semen?
Lubricating mucus
What 2 hormones control the testes?
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
What hormone does LH control?
Testosterone
Where are LH and FSH secreteed from?
Anterior pituitary
What stimulates LH and FSH secretion?
Gonadotropin-releasing hormone
What is the predominant negative-feedback effect of testosterone?
To decrease gonadotropin-releasing hormone (GnRH) release by acting on the hypothalamus, thus indirectly decreasing LH and FSH release by the anterior pituitary
What is testosterone?
A steroid hormone derived from a cholesterol precursor molecule
What are the 5 categories of testosterone effects?
1) Reproductive system before birth
2) Sex-specific tissues after birth
3) Other reproductive-related effects
4) Secondary sexual characteristics
5) Non-reproductive actions
What are 3 common disorders of the male reproductive tract?
1) Benign Prostatic Hyperplasia (BPH)
2) Prostate cancer
3) Erectile Dysfunction (ED)
What is benign prostatic hyperplasia and what causes it?
Enlargement of prostate gland caused by growth of stromal and epithelial components
What are symptoms of BPH?
Urine retention; frequent voiding; changes in bladder structure and function
What are treatments for BPH?
Surgical removal of tissue; inhibition of prostate cell growth; block muscle contraction
What is the most common cancer in men?
Prostate cancer
What are causes of prostate cancer?
Age; genetic predisposition
What kind of prostate tumours are the hardest to treat?
Recurrent hormone-independent tumours
What is erectile dysfunction?
Age-related decline in ability to sustain an erection
How does Viagra (and similar drugs) work to sustain an erection?
Inhibit cGMP loss and decrease blood flow from penis
What are 4 functions of estrogen in females?
1) Ova maturation and release
2) Establishment of female secondary sex characteristics
3) Transport of sperm from vagina to fertilization site
4) Breast development
What are 2 functions of progesterone in females?
1) Preparing suitable environment for nourishing and sustaining a developing embryo
2) Contributes to breasts’ ability to produce milk
What are oogonia?
Undifferentiated primordial germ cells in fetal ovaries
What happens to oogonia in the first part of fetal life and what is produced?
They begin early steps of first meiotic division but do not complete it; now become primary oocytes
Are primary oocytes haploid or diploid?
Diploid
When do primary oocytes complete their first meiotic division and what is produced?
Just before ovulation; produces first polar body and secondary oocytes
What happens to secondary oocytes?
They become fertilized
What does sperm entry into the secondary oocyte trigger and what does it produce?
Second meiotic division; produces secondary polar body and mature ovum
What normally interrupts the ovarian cycle?
Pregnancy
When is the ovarian finally terminated?
Menopause
What is the first half of the ovarian cycle known as?
Follicular phase
What is the second half of the ovarian cycle known as?
Luteal phase
What occurs during the follicular phase?
1) Granulosa cells of some primary follicles grow rapidly
2) Oocyte inside each follicle enlarges
3) Theca cells in follicle secrete estrogen
4) Rapid follicular growth
What happens to a follicle during ovulation?
Follicle ruptures and releases oocyte from ovary
What happens to an oocyte during ovulation?
It is released by the follicle into the peritoneal space, makes its way to the oviduct where it may or may not be fertilized
What happens to the follicle after ovulation?
The remaining granulosa cells rearrange into corpus luteum
What do the corpus luteum do?
Produces estrogen and progesterone at high levels for 14 days
What happens to the corpus luteum if the woman doesn’t become pregnant?
It disintegrates
What happens to FSH during the follicular phase?
FSH rises and signals ovarian follicle to secrete more estrogen; this rise in estrogen feeds back to inhibit FSH secretion
What happens to LH during the follicular phase?
It rises and peaks mid-cycle, triggering ovulation and rupture of dominant follicle
What does progesterone output do to other hormones?
Inhibits release of FSH and LH
What happens to the corpus luteum when there is low LH?
It disintegrates
What can LH turn on?
Steroidogenesis
What does LH secretion trigger?
Ovulation and subsequent luteinization of the ruptured follicle
What are the 4 major changes in the follicle caused by LH increase?
1) Halts estrogen synthesis
2) Reinitiates meiosis in the oocyte of the developing follicle
3) Triggers production of locally acting prostaglandins
4) Differentiation of follicular cells into luteal cells
What hormone maintains the corpus luteum?
LH
What is the most abundant hormonal product of the corpus lutuem?
Progesterone
What are the 3 phases of the uterine cycle?
1) Menstrual phase
2) Proliferative phase
3) Secretory/progestational phase
What occurs in the menstrual phase?
Discharge of blood and endometrial debris from vagina
What part of the ovarian cycle does the menstrual phase of the uterine cycle coincide with?
End of luteal phase and beginning of follicular phase
What part of the ovarian cycle does the proliferative phase of the uterine cycle coincide with and why?
Last portion of follicular phase; peak estrogen levels trigger LH surge responsible for ovulation
What happens in the proliferative phase?
Endometrium starts to repair itself and proliferate under influence of estrogen from newly growing follicles
How long does the proliferative phase last?
From end of menstruation to ovulation
When does the uterus enter the secretory phase?
After ovulation when new corpus luteum is formed
What does progesterone do to endometrium?
Converts it to highly vascularized, glycogen-filled tissue
What does loss of estrogen primarily affect?
Skeleton and cardiovascular systems
What is the climacteric?
Period of transition into menopause
Where does fertilization occur?
Upper third of oviduct (ampulla)
When MUST fertilization occur?
24 hours after ovulation
What does a blastocyst do?
Implants in endometrial lining by means of enzymes released by trophoblasts
What do enzymes do to the endometrial tissue?
Digest and carve a hole in it; also release nutrients from endometrial cells for embryo to use
When does the placenta form?
After implantation
What hormones does the placenta secrete?
Human chorionic gonadotropin, estrogen, and progesterone
Why is human chorionic gonadotropin secreted by the placenta?
Maintains corpus luteum until placenta takes over its function in the last 2 trimesters; also stimulates placenta to maintain adequate estrogen and progesterone
Why are estrogen and progesterone secreted by the placenta?
Essential for normal pregnancy
True or false: it is not normal for pregnant women to become insulin resistant
False
What happens once the placenta is delivered?
Estrogen and progesterone levels plummet allowing for lactation
What is parturition?
Labour and delivery
What does the pressure of the fetus against the cervix cause?
Increase in oxytocin secretion
What is the role of oxytocin in parturition?
1) Cause stronger contractions
2) Progressively increase positive-feedback cycle until delivery is complete
What prepares the breasts for lactation?
Placental estrogen and progesterone promote development of ducts and alveoli in mammary glands; prolactin stimulates synthesis of enzymes essential for milk production
What initiates lactation?
Withdrawal of placental steroids at parturition
How is lactation sustained?
Suckling
What does suckling trigger and what does this cause?
Release of oxytocin and prolactin; oxytocin causes milk ejection by stimulating alveoli to squeeze secreted milk out through ducts and prolactin stimulates secretion of more milk to replace ejected milk
What can happen when prolactin is high and a woman isn’t pregnant?
Pause in menstrual cycle, hence why breastfeeding mothers don’t go back to menstruating until their baby is weaned
What is amenorrhea?
No menstrual cycle
What are 3 causes of amenorrhea?
1) Pregnancy
2) Menopause
3) Stress-induced down regulation of gonadotropins
What are symptoms of polycystic ovarian syndrome?
1) Hirsutism (abnormal facial hair growth)
2) Amenorrhea
3) Infertility
True or false: polycystic ovarian syndrome is obesity associated
True
What is endometriosis?
Ectopic endometrial tissue in the abdomen
What is a symptom of endometriosis and why?
Painful menstrual cycle because endometrial tissue in the abdomen is subject to same endocrine cycles as uterus (expansion, vascularization, and sloughing)
What is a symptom of gestational diabetes?
Fetal macrosomia (high fetal insulin and growth)
