Endocrine System Flashcards
The endocrine system has what 4 functions:
• maintains homeostasis
• controls storage and utilisation of energy
• regulates growth, developments and reproduction
• responds to environmental stimuli
What are the four principle mechanisms of communication between cells
• gap junctions
• parachute (local) hormones
• hormones
• neurotransmitters
What are gap junctions
• Pores in cell membrane allow signalling molecules, nutrients and electrolytes to move from cell to cell
Paracrine (local) hormones are
• secreted into tissue fluids to affect nearby cells
Hormones are…
• chemical messengers that travel in the bloodstream to other tissues and organs
Neurotransmitters are…
• released from neurons to travel across synaptic cleft to second cell
What are the components of the Endocrine system
• Endocrine system: glands, tissues and cells
• endocrinology: study of the system and diagnosis and treatment of disorders
• endocrine glands: organs that are sources of hormones
• hormones: chemical messengers transported by the blood to stimulate physiological responses in cells of tissues and organs
What are Receptor Proteins
• 3 dimensional shape that fits a specific signal molecule
• signal molecule and receptor proteins bind, a change in the receptor protein is induced and a response in the cell is generated
What are the 2 chemical classes of hormones
• lipid soluble: passes through cell membrane and bind to receptors in the cytoplasm of cells
• water soluble: cannot pass through cell membrane. Instead binds to receptors on the surface of membranes
Anterior Pituitary Hormones
• follicle stimulating hormone (FSH)
• lutenising hormone (LH)
• thyroid stimulating hormone (TSH)
• adrenocorticotropic hormone (ACTH)
• growth hormone (GH)
Posterior pituitary hormones consist of:
(Produced by the Hypothalamus)
• Antidiuretic Hormone (ADH)
• Oxytocin (OT)
Function of the adrenal medulla
• when stimulated, releases catechilamines (adrenaline and noradrenaline) and a trace of dopamine directly into the bloodstream
• increases alertness and prepares body for physical activity
Functions of catecholamines
• mobilize high energy fuels, lactate, fatty acids and glucose
• glycogenolysis and gluconeogensis boost glucose levels
• glucose-sparing effect because inhibits insulin secretion
• muscles use fatty acids saving glucose for brain
• increases blood pressure, heart rate, blood flow to muscles, pulmonary air flow and metabolic rate
• decreases digestion and urine production
The adrenal cortex produces:
• 25 steroid hormones called corticosteroids and corticoids
Adrenal cortex secretes 5 major steroid hormones from what 3 layers of glandular tissues?
• Zona glomerulosa (thin, outer layer)
• zona fasciculata (thick, middle layer)
• zona reticularis (narrow, inner layer)
Catergories of Corticosteroids:
• mineralocorticoids
• glucocorticoids
• sex steroids
Addisons disease is:
• primary adrenal insufficiency or hypoadrenalism, a rare disorder of the adrenal glands
Causes of addisons disease:
• primary adrenal insufficiency: adrenals: autoimmune disease, genetics, surgical removal, infections, cancer
• secondary: pituitary: cancer, autoimmune disease, genetics and surgical removal
• tertiary: hypothalamus: sudden removal of corticosteroids (prescription or treatment of Cushing disease)
Signs and symptoms of Addison’s crisis:
• abdominal pain
• nausea
• diarrhoea
• fatigue
• dizziness (postural hypotension)
• pigmentation: buccal, scars, palmar creases, generalised
• Hypoglycaemia
•hypotension
•Hyperkalaemia
Where is the thyroid gland located
Just below the larynx
Function of thyroid hormones
• stimulate protein synthesis and growth
• promote maturation of the nervous system
• increase cell respiration rate
• increases digestion
• increases body temperature
Symptoms of Goitre (disease of the thyroid)
• tight feeling in the throat
• coughing
• hoarseness in voice
• dysphasia
• difficulty in breathing
Causes of giotre
- Iodine deficiency
- Graves’ disease - hyperthyroidism
- Hashimoto’s disease
- Thyroid cancer
- Thyroiditis
What is hyperparathyroidism
Glands makes too much PTH and can result in hypercalcemia, usually caused by a benign tumor.
Parathyroid disease can cause:
• osteoporosis
• kidney stones
• heart disease
• high blood pressure
Symptoms of parathyroid disease
• muscle weakness
• fatigue
• increased need for sleep
• aches and pains in joints and bones
Functions of melatonin include
• regulation of sleep-wake cycle
• regulation of immune response
• menstrual cycle regulation
• regulation of energy metabolism and glucose homeostasis
What does the pineal gland secrete
Hormone melatonin
Symptoms of hyperthyroidism
• increased metabolic rate
• weight loss
• muscular weakness and nervousness
• eyes may protrude (due to edema in orbits)
Pituitary disorders
• gigantism
• acromegaly <^caused by hypersecretion of GH
• dwarfism < hyposecretion of GH
• diabetes insipidus
• hypothesis
• prolactinoma
What hormone does the pineal gland produce
Melatonin
Role of melatonin
Regulation of sleep cycle
Regulation of immune response
Regulation of menstrual cycle
Regulation of metabolism
What is a goitre
Abnormal enlargement of the thyroid gland