21904112
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
about 4 years ago
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| Question | Answer |
| What are the 4 classes of hormones? | 1. AA derivatives (eg. adrenaline) 2. Small peptides: ADH 3. Proteins: Growth hormone, insulin 4. Steroids: cortisol, sex hormones |
| What is the difference between exocrine and endocrine secretion? | Exocrine is out of ducts to internal/extenal surfaces Endocrine is via hormones in the blood |
| What are the characteristics of: 1. Peptide 2. Steroid | 1. lots of rER, secretory vesicles 2. smooth ER, mitochondria, lipid droplets |
| Where is the pituitary gland? | In the pituitary fossa in the sphenoid bone |
| The Andenohypophysis (anterior pituitary) is formed how? | By the upgrowth of endo/ectoderm from embryonic oral cavity (Rathke's Pouch) |
| The Neurohypophysis (posterior pituitary) is formed how? | By downgrowth from floor of diencephalon |
| What does the Andenohypophysis contain? | pars distalis pars tuberalis pars intermedia |
| What does the Neurohypophysis contain? | 1. pars nervosa 2. infundibulum (pituitary/neural stalk) 3. axons of neurons supported by pituicytes |
| Which 2 peptide hormones are found in the neurohypophysis (posterior pituitary)? | 1. ADH (increase H20 retention, contracts SM) 2. Oxytoxin ( contracts SM) |
| How are hormones released by the posterior pituitary made and released? | 1. Hormones made in the cell bodies of neurons in hypothalamus as large protein 2. Cleaved into hormone+binding protein 3. Transported down axons to terminals 4. Released into fenestrated capillaries |
| What are Herring's Bodies? | Accumulations of hormones in axons |
| The Pars Distalis contains which 3 types of secretory cells? | 1. Acidophils (somatotrophs like growth hormone, mammotrophs) 2. Basophils (tyrotrophs like tyroid stim. hormone, corticotrophs, gonadotrophs) 3. Chromophobes (reserve cells) |
| Pars Tuberalis contains which cells? | Cuboidal cells with gonadotrophs |
| Pars Intermedia contains which cells? | Cells that secrete melanocyte stimulating hormone for skin pigmentation |
| How does the portal vessel system of the anterior pituitary gland work? | 1. Releasing hormones are discharged from axons of neurons from hypothalamus into pituitary portal vessels at base (top) of stalk 2. Releasing hormones travel down into anterior pituitary, stimulate target hormone release |
| What are the advantages of the portal vessel system? | 1. Need less releasing hormone 2. Hormone can be reused 3. More immediate response |
| What do releasing hormones do? | They either stimulate or inhibit anterior pituitary hormone release |
| What are some hormones with release coupled with releasing hormones? | 1. Thyrotropin 2. Gonadotropin 3. Growth Hormone 4. Corticotropin |
| What are two inhibitory releasing hormones? | 1. Somatostatin (block GH/TSH) 2. Dopamine (block prolactin) |
| What is the structure of the thyroid gland and where is it located? | 2 pear shaped lateral lobes connected by isthmus Lies at 2nd-4th tracheal rings |
| What does the thyroid gland develop from? | Downgrowth of pharyngeal pouch |
| What do the epithelial cells secrete in the thyroid gland? Where does this accumulate? | Thryglobulin (inactive form of hormone) Accumulates in follicle as colloid |
| What is covalently attached to the tyrosines of thyroglobulin to activate it? | Iodine |
| What is the function of thyroid follicular cells? | They take up iodide to oxidise to iodine |
| What happens when TSH is recieved at the anterior pituitary? | 1. Follicular cells endocytose iodinated thyroglobulin 2. Thyroglobulin broken down in lysosomes 3. Released as thyroxine (T4) or tri-iodothyronine (T3) |
| What do C cells/parafollicular cells do? What are they from? | 1. Secrete calcitonin that inhibit osteoclast activity -leads to reduced calcium concentration in blood 2. From NCCs |
| What do the chief (principle) cells in the parathyroid glands secrete? | Parathyroid hormone, which increases calcium mobilisation and blood calcium levels |
| What are the two cells present in the parathyroid gland? | 1. Principle (chief) cells 2. Oxyphil cells (no known function) |
| Where are the adrenal glands located? | At the upper part of the kidney |
| What does the medulla of the adrenal gland develop from? | The sympathetic ganglion |
| What does the cortex of the adrenal gland develop from? | The coelomic epithelium lining posterior abdominal wall |
| What does the adrenal cortex do? | They secrete steroids |
| What part of the adrenal cortex has the following? 1. cells in round clusters 2. secrete mineralocorticoids (eg. aldosterone) 3. regulated by renin/angiotensin | Zona Glomerulosa |
| What part of the adrenal cortex has the following? 1. cells arranged in straight cords running radially 2. secrete glucocorticoids (eg. cortisol) 3. Regulated by Adrenocorticotropic hormone (ACTH) | Zona Fasciculata |
| What part of the adrenal cortex has the following? 1. Irregular cords 2. Secrete mostly useless glucocorticoids/sex hormones | Zona Reticulatris |
| What does the adrenal medulla do? | Secrete catecholamines into blood: 80% adrenaline 20% noradrenaline (alpha receptors, mantain BP, continiously released vs just during stress, primary neurotransmiter of SNS) |
| What is the adrenal medulla stimulated by? Which nervous system? | Cholinergic preganglionic input from greater/lesser splanchnic nerves via coeliac ganglion Sympathetic nervous system |
| What do Alpha (20%) cells in the Islet of Langerhams produce? | Glucagon |
| What do Beta (70%) cells in the Islet of Langerhams produce? | Insulin |
| What do Delta (5-10%) cells in the Islet of Langerhams produce? | Somatostatin |
| What do G/PP (1-2%) cells in the Islet of Langerhams produce? | Pancreatic polypeptide |
| What is the diffuse neuroendocrine system? What type of secretion? | 1. Scattered cells in the gut/respiratory system that can secrete amines/peptides (eg. gastrin , CCK, secretin, serotonin) 2. Paracrine |
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