Week 6: Endocrine system Flashcards
Endocrine system organisation
1. Glands secrete various ….. into the blood
2. Hormones circulate in blood to …. …..
3. ….. cells react to the chemical messages
- Hormones
- Target tissues
- Receptor
Endocrine system: Stimulation
* Hormonal eg ACTH – released from …. ….. signalling for adrenal cortex to release ……., which work with the immune system to reduce inflammation, stimulate ….. and ……
- Humoral eg insulin – released from …. of the pancreatic islets in response to elevated blood glucose to stimulate uptake into cells by ……
- Neural – eg adrenaline/noradrenaline – …… released from adrenal medulla stimulated by increase in sympathetic nervous activity (fight or flight response)
Anterior pituitary
Glucocorticoids
Lipolysis
Gluconeogenesis
B-cells
Glut4
Catecholamines
Hormone release: Determining factors
* Quantity …..
* Rate of …… into blood
* Quantity of …… proteins present, eg sex-hormone binding globulin, corticosteroid-binding globulin, growth hormone binding globulin
* Rate of …..
* Changes in ….. ……
Synthesised
Secretion
Transport
Catabolism
Plasma volume
Hormone release: patterns
* Chronic regulation – homeostatic maintenance of ….. ….. in blood over extended period
* Acute regulation – rapid change in hormone concentration as a response to ….. ……
* …… regulation – natural variations in hormone concentration occurring at relatively consistent frequency/time (eg daily, monthly) and levels
Hormone concentration
External stimuli
Cyclic
Steroid hormones
* ….. soluble
* Diffuse through …. ……. – receptors located within the cell
* Chemical structure is derived from, or is similar to, …..
* Secreted by ….. ….(cortisol & aldosterone), ovaries (oestrogen & progesterone), testes (testosterone), placenta (estrogen & progesterone)
* General target response is to induce ….. ……
Steroid hormones
* Lipid soluble
* Diffuse through cell membranes – receptors located within the cell
* Chemical structure is derived from, or is similar to, cholesterol
* Secreted by adrenal cortex (cortisol & aldosterone), ovaries (oestrogen & progesterone), testes (testosterone), placenta (estrogen & progesterone)
* General target response is to induce protein synthesis
Non-steroid hormones
*…..-….. soluble
- Cannot diffuse through cell membranes – receptors located on ….. …..
- Two types: ….. ….. …… eg adrenaline/noradrenaline from adrenal medulla, thyroxine from thyroid or …../….. hormones eg insulin, glucagon from pancreas, IGF from liver
- General target response is to induce new …… or modify existing ones
Non-lipid soluble
Cell membrane
Amino acid derivative or protein/peptide hormones
Proteins
Hormone transport and reception
* Hormones travel in the blood to their ….. …… …..
* Receptors are …… specific and follow a …. ….. ….. only the correct hormone will fit in the correct receptor
* Each cell can have between …… and …… specific receptors
Specific target organs
Hormone, lock and key model
2,000 & 10,000
Hormone target cell specificity
Hormones alter cellular reaction of specific target cells by:
1. Stimulating ….. to alter …. ….. rate
2. Altering ….. activity rates
3. Altering cell membrane transport via ….. ……
4. Inducing …… activity
Hormone target cell specificity
Hormones alter cellular reaction of specific target cells by:
1. Stimulating DNA to alter protein synthesis rate
2. Altering enzyme activity rates
3. Altering cell membrane transport via secondary messengers
4. Inducing secretory activity
Hormone receptor binding
A target cell’s activation is dependent upon:
* …… …… in the blood
* Number of target cell ……
* Receptor sensitivity to available …… – can be up and down regulated
Hormone concentration
Receptors
Hormone
Hormone action: steroid vs non-steroid
Steroid hormone action
1. Steroid hormones enter target cell through ….. …..
2. Hormones bind with specific receptor ….. in ….. or …..
3. Hormone receptor …… activates cell DNA
4. DNA …… mRNA
5. …… leaves the cell nucleus
6. mRNA …… protein synthesis in cytoplasm
Nonsteroid hormone action
1. Non-steroid hormones bind to …… ……. on cell membrane
2. Hormone receptor complex activates …… …… within the cell
3. Adenylate cyclase forms a …… messenger, ….. …… …… adenosine monophosphate (cAMP)
4. cAMP activates protein …… that lead to cellular changes and hormonal effects
Plasma membrane
Proteins, cytoplasm, nucleus
Complex
Transcribes
mRNA
Translates
Receptor protein
Adenylate cyclase
Second
Cyclic adenosine monophosphate (cAMP)
Kinase
Endocrine glands
* Many endocrine glands in the body that release different …….
* These glands are generally …… between biological sexes, with the exception of the sex glands (ovaries, testes)
* However a small number of individuals are born with …… sets of sex glands (Intersex)
* Many glands are controlled by the …… and …… gland
Hormones
Identical
Both
Hypothalams & pituitary
Pituitary
* Once considered the “….. gland” for its regulation of other glands’ functions
* Attached to hypothalamus by ….. axons and portal ….
* Various hormones released by pituitary, including regulators for the ….., ….. and …. glands
Master
Neuronal, veins
Adrenal, thyroid & sex
Antidiuretic hormone (vasopressin)
* Plays an essential role in body …… (3)
* In response to ……. or ……, ADH released to increase water …… in the kidneys to maintain homeostasis
* During exercise sweating causes loss of ….. ….., increasing osmolarity
* Receptors sense …… ….. and …… ….., signalling for vasopressin release
* ADH increases, …… retention and …….
- Osmotic balance, blood pressure regulation and kidney function
- hypovolaemia or hypernatremia, reabsorption
- Plasma volume
- Blood volume and pressure change
- H20 retention and vasoconstriction
Growth hormone
* Promotes muscle growth and hypertrophy by facilitating?
* Directly stimulates ….. metabolism (……)
* Levels are elevated during ….. exercise in proportion to exercise …..
Amino acid transport
Fat metabolism (Lipolysis)
Aerobic, intensity
Thyroid
Triiodothyronine (T3) and thyroxine (T4)
* Increases …… and …… synthesis
* Increase size and number of …… in cells
* Promote rapid cellular uptake of ……
* Enhance …… and ……
* Increases ….. availability for oxidation
Calcitonin
* ……. calcium – important in children (decrease osteoclast activity)
Protein, enzyme
Mitochondria
Glucose
Glycolysis and glycogenesis
FFA
Metabolises
Adrenal medulla
Catecholamines (…… & ……)
* Stimulated by …… nervous system to prepare you for immediate action
* Increase rate and force of …….
* Increase FFA availability for …..
* Increase …… rate, ….. and release of glucose and ….. into blood
* Force more blood to go to the skeletal muscles through ….. and …… of specific vessels
Adrenaline & noradrenaline
Sympathetic
Heart contraction, blood pressure and respiration
Oxiation
Metabolic, glycogenolysis, FFA
Vasodilation, vasoconstriction
Adrenal cortex
Mineralocorticoids (eg ……)
* Maintain …… balance in …… fluids
Glucocorticoids (eg …..)
* Maintain consistent ….. …… levels between meals
…… (eg oestrogen, testosterone)
* Released in addition to those released by reproductive organs but in lesser amounts
Aldosterone
Electrolyte, extracellular
Cortisol, plasma glucose
Androgens
Pancreas
Insulin – secreted when plasma glucose levels are elevated (hyperglycaemia)
* Facilitates glucose transport ….. cells (……)
* Promotes …….
* …… gluconeogenesis
* Increased …… with exercise (increased uptake per receptor)
Glucagon – secreted when blood plasma glucose concentrations are …… normal (hypoglycaemia)
* Increased …….
* Increased ……
* ….. response with training
Into, GLUT4
glycogenesis
Inhibits
Sensitivity
Below
Glycogenolysis
Gluconeogenesis
Blunted
Hormone effects: glucose metabolism
* Four hormones primarily contributing to glucose release and metabolism – what are they?
- When CHO is depleted, hormones accelerate …… to ensure muscles get the energy they need
- Rate of …… breakdown into FFA and glycerol may partly determine the rate at which muscles use ….. as a fuel source during exercise
Adrenaline, noradrenaline, glucagon, cortisol
Lipolysis
Triglyceride, fat
Blood composition: Blood volume
- Total blood volume is approximately …..L in adults
- ~….ml/kg in newborns
- ~…./kg in children
- ~….ml/kg in adults
- Total blood volume increases with training (and some environment stressors)
- Composition typically maintained around …..%:…..% for plasma and living components, respectively
5L
90
75
70
55:45
Blood volume: Hematocrit
- Proportion of total …. ….. that is red blood cells (RBC)
- Lower %Hct results in reduced ….. and greater …. rate
- Higher %Hct results in lower flow rate due to ……. viscosity, RBC aggregation (…..) and ….. ….. resulting in greater shear stress
Blood volume
Viscosity, flow
Increased
Clustering
Vascular friction
Erythrocytes (RBCs)
* Typical volumes are approximately:
- …..-….. x ….. in females
- ….-…. x …. in males
* RBCs turned over/replaced every ….. days
* …… stimulates new RBC formation in bone marrow
* Young RBCs – ……. – are smaller and very …..
4.3-5.2 x 106 (to the power of 6) in females
5.1-5.8 x 108 (to the power of 8) in males
120
Erythropoietin
Reticulocytes, elastic
Haemoglobin
* Normal ranges are:
- …..-…..g/ml in females
- …..-…..g/ml in males
* Hb4 + 402 –> Hb408
* Hb increases 02 carrying capacity of blood by …..-….. fold
* ~197ml of
12-16
13-18
65-70
Exercise & haematological response
Training effects
* ……, ….. count and total ….. …. can increase with training
* Increases in PV can result in ….. haematocrit, despite RBC count increasing
* Here, RBC increased by ……% and PV by …..% however Hct is 2.2% lower (dilutional anaemia)
* Still performance greatly improved due to greater total blood volume, increased blood flow and greater 02 carrying capacity
Plasma volume, RBC count and total blood volume
Decreased
6.7%, 9.1%
Anaemia & sports
* RBC destruction > RBC replacement leads to …..
- …… deficiency
- GI and urinary tract (haematuria) …..
- Mechanical …… (measure haptoglobin)
- Osmotic damage
* Gastrointestinal (GI) ….. through anti-inflammatory drugs, mechanical or ischemia
* Psuedoanaemia (Sports/dilutional anaemia)
Anaemia
Dietary
Bleeding
Haemolysis
Loss
Erythropoietin production
Controls
* Erythropoietin (EPO) – direct stimulus for …… production
* ……. hormone
* ….. major producer of EPO
* Liver ….. contributor
* Stimulus for production is based on the …….
Stimulus
* …… or excess RBC destruction (runners haemolysis)
* …… 02 availability (altitude, sickness)
* Increased …… demands for 02
* Negative feedback control – blood borne EPO stimulates bone marrow cells already committed to increase RBC production
Erythrocyte
Glycoprotein
Kidney
Minor
Ability to transport sufficient 02 to meet tissue demands
Haemorrhage
Reduced
Tissue
Erythropoietin – …… hormone
* Genetically ……
* Originally for …… failure patients
* Now endurance athletes use/abuse
* Can increase %Hct from …..-…..%
* When combined with ….. can have fatal effects eg heart failure
Recombinant
Engineered
Renal
45-65%
Dehydration
Erythropoietin – sex differences
* Testosterone stimulates EPO production in ……
* Female sex hormones ….. stimulate EPO production
* May explain:
- Increase in ….. in males
- Increase in ….. in males
Kidneys
Don’t
RBC’s
HB
Exercise & haemoconcentration
* Blood pressure and … contraction force fluid ….. of plasma
* Muscles accumulate ….. and thus draw fluid from plasma
* Sweating results in plasma volume ….. from ….. fluid losses
* Can drop …..-….% with exercise
* Post-exercise ….. may contribute to the restoration (and supercompensation) of plasma volume after exercise bouts
* Changes in PV are very …… (…. …..)
* Trained athletes can increase by …..% after training
Out
Metabolites
Reduction, ECV
10-20%
Hypotension
Transient (3 days)
20%
Exercise and blood
Short-term effects
Viscosity increased due to:
* …… plasma volume (sweating, fluid shift)
* …… plasma total proteins (fibrinogen)
* …… RBC accumulation
Increased plasma osmolarity
* Due to fluid losses from …..
* Increased …… per litre of fluid (eg electrolytes)
* Alters osmotic gradients, may draw fluid from ….. …… (ICV)
Long-term effects
* Increased …., …. and …. (….%)
* …… %Hct
* …….. young RBC
- Increased 2,3 DPG (02 transport)
- Increased ……. – elastic membrane
* V02max inversely related to:
- …..
- …… ……
Decreased
Increased
Increased
Sweat
Solutes
Intracellular volume
Increased PV, RBC and TBV (20%)
Decreased
Increased
Deformability
HCT, Blood viscosity
