Physiology for General Surgical Sciences Examination (GSSE)
()
About this ebook
This book is designed as a learning tool to assist candidates to become familiar with the common, yet often complex, physiology topics covered in the GSSE examination. Its aim is to give candidates ideas to focus their studies in high yield areas. It is specially designed for the GSSE exam, which is a requirement for applying any surgical program in Australia and New Zealand. An important component of the guide is diagrams to aid better understanding of normal human physiology. Great care has been taken to ensure the subject and emphasis of the questions accurately simulates the actual exam.
The book is organized in 5 chapters, totaling 140 pages including colour images, diagrams and tables. This is an accompany book with Anatomy for the Generic Surgical Sciences Examination (GSSE), Springer, 2017, which is written by the same author.
Related to Physiology for General Surgical Sciences Examination (GSSE)
Related ebooks
Atlas of Pediatric Hepatology Rating: 0 out of 5 stars0 ratingsFast Facts: Acute and Recurrent Pancreatitis: Using evidence to support treatment Rating: 0 out of 5 stars0 ratingsAcute Surgical Topics: An Infographic Guide Rating: 0 out of 5 stars0 ratingsNaplex Complete Study Outline A Topic-Wise Approach Diabetes Rating: 4 out of 5 stars4/5Fast Facts: Hyperlipidemia: Bringing clarity to lipid management Rating: 0 out of 5 stars0 ratingsManaging Women’s Hyperandrogenism Rating: 0 out of 5 stars0 ratingsGastroparesis: A Comprehensive Approach to Evaluation and Management Rating: 0 out of 5 stars0 ratingsGastrointestinal Anatomy and Physiology: The Essentials Rating: 0 out of 5 stars0 ratingsFast Facts: Neurogenic Dysphagia Rating: 0 out of 5 stars0 ratingsNuclear Medicine Companion: A Case-Based Practical Reference for Daily Use Rating: 0 out of 5 stars0 ratingsPhytochemicals for Diabetic Complications Rating: 0 out of 5 stars0 ratingsPediatric Liver Intensive Care Rating: 0 out of 5 stars0 ratingsIntegrated Endocrinology Rating: 0 out of 5 stars0 ratingsLabs & Imaging for Primary Eye Care: Optometry In Full Scope Rating: 0 out of 5 stars0 ratingsClinical Surgery Review 2023: For USMLE Step 2 CK and COMLEX-USA Level 2 Rating: 0 out of 5 stars0 ratingsEmergencies in Diabetes: Diagnosis, Management and Prevention Rating: 0 out of 5 stars0 ratingsAnesthesia for Hepatico-Pancreatic-Biliary Surgery and Transplantation Rating: 0 out of 5 stars0 ratingsMenstrual Cycle Related Disorders: Volume 7: Frontiers in Gynecological Endocrinology Rating: 0 out of 5 stars0 ratingsEssentials in Lung Transplantation Rating: 0 out of 5 stars0 ratingsContinuous Glucose Monitoring Rating: 0 out of 5 stars0 ratingsFast Facts: Déficit en pyruvate kinase: Sensibilisation à cette maladie génétique rare Rating: 4 out of 5 stars4/5Histopathology of Chronic Constipation Rating: 0 out of 5 stars0 ratingsBasic Monitoring in Canine and Feline Emergency Patients Rating: 1 out of 5 stars1/5Leptin: Regulation and Clinical Applications Rating: 0 out of 5 stars0 ratingsEureka: Physiology, second edition Rating: 0 out of 5 stars0 ratingsGuide to Pediatric Urology and Surgery in Clinical Practice Rating: 0 out of 5 stars0 ratingsPuzzles in General Surgery: A Study Guide Rating: 4 out of 5 stars4/5Intralipid Rating: 0 out of 5 stars0 ratingsMetabolic Disorders and Critically Ill Patients: From Pathophysiology to Treatment Rating: 0 out of 5 stars0 ratingsPharmacology Review Study Guide for Exams Rating: 0 out of 5 stars0 ratings
Medical For You
The Lost Book of Simple Herbal Remedies: Discover over 100 herbal Medicine for all kinds of Ailment, Inspired By Dr. Barbara O'Neill Rating: 0 out of 5 stars0 ratingsWhat Happened to You?: Conversations on Trauma, Resilience, and Healing Rating: 4 out of 5 stars4/5Mating in Captivity: Unlocking Erotic Intelligence Rating: 4 out of 5 stars4/5Brain on Fire: My Month of Madness Rating: 4 out of 5 stars4/5Gut: The Inside Story of Our Body's Most Underrated Organ (Revised Edition) Rating: 4 out of 5 stars4/5Adult ADHD: How to Succeed as a Hunter in a Farmer's World Rating: 4 out of 5 stars4/5The Vagina Bible: The Vulva and the Vagina: Separating the Myth from the Medicine Rating: 5 out of 5 stars5/5Mediterranean Diet Meal Prep Cookbook: Easy And Healthy Recipes You Can Meal Prep For The Week Rating: 5 out of 5 stars5/5The Emperor of All Maladies: A Biography of Cancer Rating: 5 out of 5 stars5/5Hidden Lives: True Stories from People Who Live with Mental Illness Rating: 4 out of 5 stars4/5A Letter to Liberals: Censorship and COVID: An Attack on Science and American Ideals Rating: 3 out of 5 stars3/5The Little Book of Hygge: Danish Secrets to Happy Living Rating: 4 out of 5 stars4/5The Song of the Cell: An Exploration of Medicine and the New Human Rating: 4 out of 5 stars4/5Holistic Herbal: A Safe and Practical Guide to Making and Using Herbal Remedies Rating: 4 out of 5 stars4/5The Diabetes Code: Prevent and Reverse Type 2 Diabetes Naturally Rating: 4 out of 5 stars4/5I'm So Effing Tired: A Proven Plan to Beat Burnout, Boost Your Energy, and Reclaim Your Life Rating: 3 out of 5 stars3/5Herbal Healing for Women Rating: 4 out of 5 stars4/5Living Daily With Adult ADD or ADHD: 365 Tips o the Day Rating: 5 out of 5 stars5/5Women With Attention Deficit Disorder: Embrace Your Differences and Transform Your Life Rating: 5 out of 5 stars5/5Tight Hip Twisted Core: The Key To Unresolved Pain Rating: 4 out of 5 stars4/5Extra Focus: The Quick Start Guide to Adult ADHD Rating: 5 out of 5 stars5/5This Is How Your Marriage Ends: A Hopeful Approach to Saving Relationships Rating: 4 out of 5 stars4/5"Cause Unknown": The Epidemic of Sudden Deaths in 2021 & 2022 Rating: 5 out of 5 stars5/5Blitzed: Drugs in the Third Reich Rating: 4 out of 5 stars4/5The Obesity Code: the bestselling guide to unlocking the secrets of weight loss Rating: 4 out of 5 stars4/5
Reviews for Physiology for General Surgical Sciences Examination (GSSE)
0 ratings0 reviews
Book preview
Physiology for General Surgical Sciences Examination (GSSE) - S. Ali Mirjalili
© Springer Nature Singapore Pte Ltd. and People's Medical Publishing House Co. Ltd. 2019
S. Ali Mirjalili (ed.)Physiology for General Surgical Sciences Examination (GSSE)https://doi.org/10.1007/978-981-13-2580-9_1
1. Endocrine and Reproductive Physiology
S. Ali Mirjalili¹ , Lucy Hinton² and Simon Richards³, ⁴
(1)
Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
(2)
Department of General Surgery, Tauranga Hospital, Tauranga, New Zealand
(3)
Department of General Surgery, University of Otago, Christchurch, New Zealand
(4)
Christchurch Hospital, Christchurch, New Zealand
S. Ali Mirjalili
Email: [email protected]
Keywords
HypothalamusPituitaryCalcium
1.1 Mechanisms of Hormonal Action
Short notes
Three main types of hormones:
1.
Steroid (Lipid soluble): Synthesised from cholesterol. Diffuse out of cell through phospholipid bi-layer. Need to be bound to plasma proteins.
2.
Peptide/Protein (Water soluble): Usually formed from a precursor, which is cleaved prior to leaving the cell. Stored in cytoplasmic granules. Released by exocytosis.
3.
Amino acid tyrosine derivatives (Water soluble): Thyroid and adrenal medulla hormones.
Function of hormones:
Hormones may act at the cell surface or diffuse into the cell to act on nuclear receptors:
Hormones may act by entering the cell surface → cytoplasmic/nuclear receptors → modify mRNAs
e.g. thyroid hormones, steroid hormones, vitamin D
Steroid hormones can diffuse (or be transported) through the cell membrane
Binding may occur in the cytoplasm or nuclear membrane
Receptor may then bind to specific parts of the DNA (serum response element or SRE) and regulate mRNA transcription
Hormones may function by acting at the cell surface
By altering ion movements (often regarded as neurotransmitters) and binding directly to ion channels
e.g. Na+ – K+, GABA/glycine – Cl−, Nicotinic Acetylcholine receptor
By ↑ or ↓ adenylate cyclase → ↑ or ↓ production of cyclic AMP (cAMP), by converting ATP to cAMP via G-proteins. cAMP binds to the regulatory subunit of a specific protein kinase
e.g. PTH, TSH, Glucagon, ACTH, Catecholamines via beta-1 receptors → ↑ cAMP
Catecholamines acting via alpha-2 →↓ cAMP
By ↑ guanylate cyclase → ↑ cGMP → e.g. ANP and NO. Similar process as above. Initial action may span the cell membrane [with intra and extracellular functions (ANP)], or act entirely intracellularly (NO)]
By activating phospholipase C → hydrolysis of cell membrane phospholipids → IP3 and diacylglycerol
IP3 → binds to ER → Ca²+ release (3rd messenger)
Diacylglycerol → ↑ protein kinase C → phosphorylates proteins and alters their function
e.g. vasopressin, TRH, angiotensin II, catecholamines via alpha receptors
By acting on tyrosine kinase → ↑ activity
Occurs by spanning membrane → activates tyrosine kinase
e.g. insulin, EGF, PDGF
By linking to intracellular tyrosine kinase
e.g. cytokines, GH
1.2 Hypothalamus and Posterior Pituitary
Questions
1.
How is thirst controlled by the hypothalamus?
By sensing changes in plasma osmolarity through osmoreceptors (anterior hypothalamus)
By sensing blood volume changes through angiotensin II
By sensing blood volume changes through baroreceptors peripherally
2.
Explain the control mechanism for release of hormones from the posterior pituitary.
Posterior pituitary hormones are synthesised by cell bodies in the hypothalamus. These cells are known as magnocellular neurons in the supraoptic and paraventricular nuclei of the hypothalamus. The pathway from the hypothalamus to the posterior pituitary is called the hypothalamo-neurohypophyseal tract. The hormones (ADH and oxytocin) are stored in vesicles, which are released following various neural stimuli.
3.
Explain the mechanism of action of ADH.
Its main action is to prevent the loss of water in the kidneys by concentrating urine.
Acts on renal collecting ducts to ↑ permeability to water passing from urine to medullary fluid (via V2 → cAMP → ↑ water channels from endosomes)
Secondary actions are;
Increases urea permeability in the collecting ducts of the inner medulla of the kidney
Vasoconstriction via V1a → G-protein → ↑ in Ca²+ → blood vessel constriction
Seen in liver, brain, kidney, mesangial cells
Stimulation of ACTH release by corticotrophins in the anterior pituitary via V1b → G-protein → Ca²+ release
Stimulation of glycogen breakdown in the liver
4.
What are the effects of oxytocin?
Contraction of myoepithelial cells in the breast → milk ejection
Contraction of smooth muscle of uterus
ADH effect in high concentrations
5.
What is diabetes insipidus?
This is a condition where the body has an abnormal inability to secrete or respond to ADH. May be due to destruction (neoplasm/trauma) of hypothalamus (neurogenic) leading to lack of ADH, or due to inability of the kidney (nephrogenic) to respond to ADH (acquired or genetic). It results in water loss through the kidneys resulting in polydipsia, polyuria (often >20 L/day) and thirst.
Short notes
Functions of the hypothalamus
1.
Control of anterior pituitary hormone secretion (via releasing hormones) see text of anterior pituitary.
2.
Control of appetite
Lateral feeding centre chronically active but suppressed by satiety centre and possibly CCK and leptin
Ventrolateral satiety centre senses glucose utilisation and is insulin sensitive
3.
Role in cyclic phenomena - circadian rhythms, body temperature
4.
Control of thirst
By sensing changes in plasma osmolarity through osmoreceptors (anterior hypothalamus)
By sensing blood volume changes through angiotensin II
By sensing blood volume changes through baroreceptors peripherally → nerves
5.
Control of posterior pituitary secretion (vasopressin/ADH, oxytocin)
Formed as preprohormones
6.
Vasopressin (ADH)
Stimulated by anti-diuretic hormone mechanisms
↑ in plasma osmotic pressure (sensed by anterior hypothalamus)
↓ in plasma volume (sensed by baroreceptors – overrides osmotic effect)
Angiotensin II
Stress and pain
Drugs (morphine, nicotine)
Sleep
Inhibited by pro-diuretic mechanisms
↓ in plasma osmotic pressure
↑ in plasma volume
Alcohol
Not bound in plasma, readily distributed, degraded by proteolysis
Actions
Antidiuretic action
Acts on collecting ducts to ↑ permeability to water passing from urine to medullary fluid (via V2 receptor→ cAMP → ↑ water channels from endosomes)
Increases urea permeability in the collecting ducts of the inner medulla of the kidney
Vasoconstriction
Via V1a receptor → G-protein → ↑ in Ca²+ → blood vessel constriction
Seen in liver, brain, kidney, mesangial cells
Stimulation of ACTH release by corticotrophins in the anterior pituitary via V1b receptor→ G-protein → Ca²+ release
Stimulation of glycogen breakdown in the liver
Diabetes insipidus
May result from destruction (neoplasm / trauma) of hypothalamus (neurogenic) leading to a lack of ADH, or due to inability of the kidney (nephrogenic) to respond to ADH (acquired or genetic)
7.
Oxytocin (hormone related to ADH)
Stimulated by mechanical vaginal distension, nipple stimulation, stress
Inhibited by Alcohol
Actions:
Contraction of myoepithelial cells in the breast → milk ejection
Contraction of smooth muscle of uterus
ADH effect in high concentrations
Effects mediated by specific receptor → G protein → Ca²+ release
Number of receptors increases dramatically during late stages of pregnancy
8.
Pineal gland
Secretes melatonin cyclically (high at night, low during the day)
1.3 Anterior Pituitary
Questions
1.
Which cells of the anterior pituitary release TSH, LH, FSH, ACTH, GH and Prolactin?
2.
What stimulates the release of GH?
Its release occurs when there is a decrease in metabolic fuels [e.g. hypoglycaemia, ketosis] as well as stress, sleep, glucagon, fasting and L-dopa.
3.
What is somatostatin?
This is a hormone, also known as growth hormone–inhibiting hormone (GHIH), which is released by the hypothalamus and inhibits release of GH.
4.
What are the direct effects of GH release?
Think of GH as increasing protein stores, decreasing fat stores and conserving carbohydrates.
Direct effects of GH include:
Carbohydrate: ↓ glucose uptake by cells, stimulates hepatic glucose output and ↑ insulin secretion.
Fat: Stimulates lipolysis and mobilisation of fatty acids from adipose tissue, ↑ conversion of fatty acids to acetyl coenzyme A
Protein: ↑ amino acid uptake, ↑ RNA translocation, ↓ catabolism of protein and amino acids.
Bone: ↑ protein deposition, ↑ cell reproduction, ↑ osteogenic cells
Stimulates erythropoiesis
5.
What are somatomedins?
Somatomedins are a group of proteins released from the liver that promote cell growth and division in response to stimulation by growth hormone (GH)
Short notes
Hormones of the Anterior Pituitary
Release is regulated by the hypothalamus
Glycoproteins are composed of an α subunit (identical) and β subunit (differs)
Please see texts for details on TSH, LH and FSH, ACTH
Growth Hormone (GH)
Does not act on a specific organ but exerts its effect directly on almost all tissues of the body.
Related structurally to prolactin
Circulates bound to carrier proteins with a t ½ of 20 min
Secretion is pulsatile
Presence of fuels inhibits secretion and vice versa
↑ by GHRH (Growth hormone releasing hormone) in response to
↓ in metabolic fuels (e.g. ketosis, hypoglycaemia), certain amino acids, stress, deep sleep, sex steroids, glucagon, exercise, fasting, ghrelin, and L-dopa.
↓ by GHIH (Growth hormone inhibitory hormone/somatostatin) in response to
Free fatty acids, glucose
IGF-I (insulin-like growth factor-I) provides negative feedback
Stimulates IGF-I production by the liver
Think of GH as increasing protein deposition, decreasing fat stores and conserving carbohydrates.
Direct effects of GH include
Carbohydrate: ↓ glucose uptake by cells, stimulates hepatic glucose output and ↑ insulin secretion.
Fat: Stimulates lipolysis and mobilisation of fatty acids from adipose tissue, ↑ conversion of fatty acids to acetyl coenzyme A
Protein: ↑ amino acid uptake, ↑ RNA translocation, ↓ catabolism of protein and amino acids.
Bone: ↑ protein deposition, ↑ cell reproduction, ↑ osteogenic cells
Stimulates erythropoiesis
Indirect effects are mediated through IGF-I (somatomedins) from the liver.
Receptor is large and stimulates intracellular kinases
Insulin like effects, glucose uptake, anti-lipolysis etc
Other family members include EGF, NGF, PDGF
Type I receptors bind IGF-I > IGF-II
Type II receptors bind IGF II > IGF I
Insulin receptors bind insulin > IGF I
Prolactin
Secreted by lactotrophs, usually under chronic inhibition via dopamine
Secretion ↑ by
Nipple stimulation, stress, pregnancy, hypoglycaemia, oestrogens, exercise
Secretion ↓ by
L-dopa, bromocriptine
Under normal negative feedback loops, t ½ of 20 min
Promotes milk secretion by the breasts
High concentrations of prolactin inhibit LH and FSH action on the gonads and can cause infertility
1.4 Adrenal Medulla
Questions
1.
What are catecholamines derived from?
The amino acid tyrosine (Fig. 1.1).
2.
Where is PNMT (phenylethanolamine-N-methyltransferase) found?
This is the enzyme that converts noradrenaline to adrenaline. It is found in the adrenal medulla and the brain.
3.
What hormone is secreted in the largest quantity from the adrenal medulla?
Adrenaline. Converted from noradrenaline by the enzyme PNMT (phenylethanolamine-N-methyltransferase). Chromaffin cells