EXAM 1 Neuro and Endocrine Pathophysiology Flashcards
Cell communications: What are gap junction?
Pores in the cells membrane allowing signaling to move from cell to cell
What are neurotransmitters?
Release from neuron to travel across gap to a 2nd cell
What are paracrine hormones?
Local hormones secreted into tissue fluids to affect nearby cells
Strict definition of hormones
Chemical messengers that travel in the bloodstream and stimulate response in another tissue or organ
What are target cells?
They have receptors for hormone
Endocrine hormones
Produce hormones
Endocrine system : endocrine organs are
Thyroid , pineal, etc
Endocrine system: also produce
hormone producing cells organs (Brain, heart, and small intestine)
***Endocrine control : normal homeostatic control of what? MEWGIH
Metabolism Electrolyte balance (Na, K, Ca2+) Water retention and BP control Glucose levels Inflammation Healing
Normal vs disease states complicated usually by?
Elevated stress of illness/surgery
***Hormone regulation: levels of hormone, what happens?
levels maintained within a certain range for normal physiologic function
***Hormone regulation is mainly controlled by what feedback?
Negative feedback
What are the environmental factors that can affect levels of hormones? (SSSND)
Stress (both physical and mental) Systemic illness Sleep patterns Nutritional changes Day-night cycle
Hormone Regulation: Most pituitary hormones exhibit what?
Circadian rhythm
During hormone regulation, it ensure
Peak hormone levels at times of greatest demand
When does peak secretion of ACTH and cortisol?
Occur early in the morning
What is stress caused by?
Any situation that upsets homeostasis via physical or emotional causes
What is general adaptation syndrome?
The way the body reacts to stress
What are the 3 stages of general adaptation syndrome?
Alarm REACTION
Stage of RESISTANCE
Stage of EXHAUSTION
Alarm reaction is the _________
What happens?
Initial response
Increase Epinephrine and norepinephrine levels
HR and BP and blood glucose (NEHBB) (NaH2O
Sodium and water retention (aldosterone)
Stage of Resistance what happens?
GACFatGDS
Glycogen reserves gone Increase ACTH and cortisol levels Fat and protein breakdown Gluconeogenesis Depresses immune function Susceptibility to infection and ulcers
Stage of Exhaustion is defined as
stress that continues until fat reserves are gone
What happens during stage of exhaustion? Protein
PL HE HA
Protein breakdown and muscle wasting
Loss of glucose homeostasis
Hypertension and electrolyte imbalances (loss of K+H+)
Hypokalemia and alkalosis (can lead to death)
***Effects of stress : What is activated and what does it depend on?
Activation of the adaptive processes to stress depends on the severity and or duration of the stressor event
***Effects of stress when adaptive process activated , 3 different outcomes possible
- Restoration of homeostasis
- Inadequate response
- Exaggerated response
***Stress response : a modified endocrine response
Causing physical and mental changes
***Modified endocrine response: what physical changes occur?
There is redirection of blood flow
Decreased to GLK (gut, liver and kidney)
Increased to HBLS (Heart, brain, liver and skeletal muscle)
***Modified endocrine response: what mental changes occur?
Increased alertness and arousal, cognition, analgesia
inhibition of appetite (Improved CAAA IA)
***Hemodynamic & Metabolic Changes in stress leads to redirection of blood flow
Increase HR, CO and Metabolism with hyperglycemia (HCML) Lypolysis
Decreased insulin
Neuroendocrine effectors of Stress response: What are the peripheral effectors? (GEN)
Glucocorticoids
Epinephrine
Norepinephrine
Neuroendocrine effectors of Stress response: What are the central effectors? (CV)
Corticotropin Releasing hormone (CRH): { (CRH –>Pituitary –> ACTH)}
Vasopressin (ADH) Increase BP
Hypothalamic-Pituitary-Adrenal Axis (HPA-axis) stress reaction (CAA)
CRH stimulate release of ACTH from hypothalamus
Acts with Vasopressin to control pituitary adrenal axis
ACTH leads to cortisol release
What is the most important regulator of ACTH release?
CRH
***What are other components affecting HPA ? What does it depends on ? (CIAL)
Depending on the magnitude of the stress, additional factors to enhance HPA response are:
Cytokines (TNF)
Interlukins (IL-6 & IL-1)
Angiotensin II
Lipid mediators of inflammation (Arachidonic acid –>Prostaglandins & Leukotrienes)
***Short term stress (CLR)
Cortisol regulates CRH, Vasopressin & ACTH via negative feedback
Limits exposure of tissues to cortisol
Reduces excessive metabolic, CV, and Immune
stress response
***Long Term Stress examples (CAMPA)
Chronic illness/depression Anorexia nervosa Malnutrition Panic disorder Alcohol withdrawal
***Long term stress Sequela:(GIPI)
Increased gluconeogenesis, insulin resistance, protein catabolism, immune depression (GIPI)
Exocrine Glands vs Endocrine glands: Exocrine glands
secrete their product through a duct and onto an open surface or organ cavity. Extracellular effects (food digestion)
Exocrine Glands vs Endocrine glands: Endocrine glands
Secrete their products directly into the bloodstream, no ducts. Intracellular effects (Alter target cell metabolism)
Nervous vs Endocrine Systems: Communication
Nervous : both chemical and electrical
Endocrine: Only CHEMICAL
Nervous vs Endocrine Systems: Speed and persistence of response
Nervous: reacts quickly , stops quickly
Endocrine: react slowly . effect may continue for weeks
Nervous vs Endocrine Systems: Adaptation to long term stimuli
Nervous: response declines (adapt quickly)
Endocrine: response persists
Nervous vs Endocrine Systems: Area of effect
Nervous: Targeted and specific (one organ)
Endocrine: general, widespread effects (many organs)
What are chemical that function as both hormones and neurotransmitters? CANT Do
Cholecystokinin ADH NE Thyrotropin releasing hormone (TRH) Dopamine
Some hormones are secreted by neuroendocrine cells
Oxytocin and catecholamine
Both Nervous and endocrine systems have
overlapping effects on same target cells
Both cause glycogenolysis in the liver
NE and Glucagon
Both nervous and endocrine systems can regulate each other, How so?
Neurons trigger hormone secretion
Hormones stimulate or inhibit neurons
Hypothalamus description
Flattened funnel, forms floor and wall of third ventricle
What is the function of the hypothalamus?
Regulates homeostasis mechanisms and some endocrine functions.
Where is the pituitary gland hypophysis
Suspended by hypothalamus by stalk (infundibulum)
Where is the pituitary gland located?
House in SELLA TURCICA of sphenoid bone
1.3 cm diameter
Where is the Anterior pituitary ?
The anterior pituitary (Adenohypophysis) arises from hypophyseal pouch (outgrowth of pharynx)
Where is the Posterior pituitary ?
Also called neurohypophysis (arises from brain)
Oxytocin released by
Posterior pituitary gland
Pituitary Hormones - Anterior Lobe : What types of hormones?
Tropic hormones target other endocrine hormones
What are the Gonadotropins hormones?
Target gonads (FSH and LH)
What are the Anterior lobes hormones?
FLAT PG FSH LH ACTH TSH PRL GH
Axis refer to
Way endocrine glands interact
What is the role of FSH?
Stimulates production pf egg or sperm cells
What is the role of LH? In female
Mainly stimulates hormone production
Female: stimulates ovulation and secretion of estrogen and progesterone
What is the role of LH in males?
Stimulates testes to secrete testosterone
What is the role of TSH?
Stimulates growth of thyroid and secretion of thyroid hormones
What is the role of ACTH (adrenocorticotropic hormone)
Regulates response to stress, stimulates adrenal cortex
What does corticosteroids regulated?
Glucose, Fat, and protein metabolism
What is the role of Prolactin (Prolactin releasing factor) ?
stimulates anterior pituitary produce it
Prolactin in female
Milk synthesis after delivery
Prolactin in male
Increase LH sensitivity and increase Testosterone secretion
Growth hormones aka
somatotropin
Where is the GH secreted?
Anterior pituitary
Growth hormone promotes
Tissue growth
Growth hormones promote tissue growth 2 ways
Mitosis and cellular differentiation
Stimulates liver to produce IGF-I and II
Growth hormone , liver protein synthesis
Increase DNA transcription for Increase mRNA production, proteins synthesized
Enhanced amino acid transport into cells, decrease protein catabolism
Growth hormone , Lipid metabolism how?
GW stimulates FFA and glycerol release from adipocytes, protein sparing.
Growth hormone, CHO metabolism
Glucose sparring effect = less glucose used for energy
Growth hormone, Electrolyte balance
Promotes Na+, K+, Cl- retention, Ca2+ absorption
Growth Hormone and Aging: Childhood and adoslescence
Bone, cartilage, and muscle growth
Stimulates growth at Epiphyseal plates
Growth Hormone and Aging: Adulthood
Increase osteoblastic activity and appositional growth affecting bone thickening and remodeling.
Growth hormone and aging, what changes occur in concentration
Blood concentration decrease by age 75 to 1/4 of that of adolescent.
Levels of GH throughout the day _______
fluctuates
GH is higher during (SAV)
Sleep, after high protein meals, vigorous exercise
GH is lower
After High CHO meals
Posterior Pituitary Hormones produced by
Hypothalamus
Posterior Pituitary Hormones are
AGO
ADH
GnRN (Gonadotropin-releasing hormone)
Oxytocin
What is the role of ADH?
targets kidneys, Increase water retention, reduce urine
Also a neurotransmitter
Acts as both Neurotransmitter and hormones?
ADH
Oxytocin role ? Causes
Causes uterine contractions and milk ejection (letdown)
Stimulates production of FSH and LH
GnRH
Pituitary is under control of
Hypothalamic and Cerebral control
Anterior lobe control
Releasing hormones and inhibiting hormones of hypothalamus
Posterior lobe control
Neuroendocrine reflexes
Posterior lobe control hormone release in response to NS signals
hormones release in response to nervous system signals
Sucking infant –> stimulates nerve ending –> Hypothalamus –> posterior lobe –>oxytocin –> milk ejection
Hormone release in response to higher brain centers
Milk ejection reflex can be triggered by a baby’s cry
What is negative feedback?
Increase target organ hormone levels inhibits release of tropic hormones