The adrenal glands consist of an outer cortex and inner medulla. The cortex produces mineralocorticoids like aldosterone and glucocorticoids like cortisol. Cortisol regulates metabolism and immune function. Aldosterone regulates sodium and potassium levels. Their release is controlled by the HPA axis and renin-angiotensin system. The medulla produces catecholamines like epinephrine and norepinephrine which increase heart rate and blood pressure through adrenergic receptors. Together these hormones help regulate vital processes and the stress response.
anatomy and physiology of adrenal cortex . detail of artery and venous supply along with histological differences of adrenal cortex . detail of biosynthesis of adrenocorticosteroids. reaction of biosynthesis of cortisol , androgen and aldosterone in different region ie. zona fasciculata, zona reticularis and zona glomerulosa respectively. biochemical function of cortisol and aldosterone along with structures. congenital adrenal hyperplasia.
anatomy and physiology of adrenal cortex . detail of artery and venous supply along with histological differences of adrenal cortex . detail of biosynthesis of adrenocorticosteroids. reaction of biosynthesis of cortisol , androgen and aldosterone in different region ie. zona fasciculata, zona reticularis and zona glomerulosa respectively. biochemical function of cortisol and aldosterone along with structures. congenital adrenal hyperplasia.
enlists and the description of the different descending tracts of the CNS. cortico spinal tract, cortico bulbar tract, extra pyramidal and pyramiddal tracts, homunculus, vestibulospinal tract, reticulo spinal tracts, tectospinal tract, autonomic tract, uppermotor neuron lesion, lower motor neuron lesion, spinal cord injury, brown sequard syndrome. spinal cord infection, degenerative disorders of spinal cord,
Introduction
HORMONES OF ADRENAL CORTEX
MINERALOCORTICOIDS
Aldosterone
Life-saving Hormone
Actions of aldosterone
Aldosterone escape or escape phenomenon
Regulation of aldosterone secretion
Renin–angiotensin system
Applied
enlists and the description of the different descending tracts of the CNS. cortico spinal tract, cortico bulbar tract, extra pyramidal and pyramiddal tracts, homunculus, vestibulospinal tract, reticulo spinal tracts, tectospinal tract, autonomic tract, uppermotor neuron lesion, lower motor neuron lesion, spinal cord injury, brown sequard syndrome. spinal cord infection, degenerative disorders of spinal cord,
Introduction
HORMONES OF ADRENAL CORTEX
MINERALOCORTICOIDS
Aldosterone
Life-saving Hormone
Actions of aldosterone
Aldosterone escape or escape phenomenon
Regulation of aldosterone secretion
Renin–angiotensin system
Applied
A small gland that makes steroid hormones, adrenaline, and noradrenalineRuvarasheMutadza1
A small gland that makes steroid hormones, adrenaline, and noradrenaline. These hormones help control heart rate, blood pressure, and other important body functions. There are two adrenal glands, one on top of each kidney. Also called suprarenal gland.
In mammals, the adrenal glands (also known as suprarenal glands) are endocrine glands that sit at the top of the kidneys. They are chiefly responsible for releasing hormones in response to stress through the synthesis of corticosteroids such as cortisol and catecholamines such as adrenaline (epinephrine) and noradrenaline. They also produce androgens in their innermost cortical layer. The adrenal glands affect kidney function through the secretion of aldosterone, and recent data (1998) suggest that adrenocortical cells under pathological as well as under physiological conditions show neuroendocrine properties; within normal adrenal glands, this neuroendocrine differentiation seems to be restricted to cells of the zona glomerulosa and might be important for an autocrine regulation of adrenocortical function.
Structure and function of adrenal glandsMoses Kayungi
Structure and function of adrenal glands
• Anatomically, the adrenal glands (suprarenal) are located in the thoracic abdomen situated 'on' top of the kidneys one on each side, specifically on their anterosuperior aspect.
• They are surrounded by the adipose capsule and the renal fascia
• They consist of two parts,
The outer cortex
The inner medulla.
Adrenal Cortex
• The adrenal cortex is devoted to the synthesis of corticosteroid hormones from cholesterol.
It completes the hypothalamic-pituitary-adrenal axis
The source of cortisol and corticosterone hormones
• The cortex is divided into three zones, or layers.
• This division is sometimes referred to as ‘functional zonation”
Zona glomerulosa
Zona fasciculata
Zona reticularis
Adrenal Medulla
• The adrenal medulla is the core of the adrenal gland, and is surrounded by the adrenal cortex.
• The chromaffin cells of the medulla are the body's main source of the circulating catecholamines, adrenaline (epinephrine) and noradrenaline (norepinephrine
Blood supply to Adrenal Gland
• Although variations of the blood supply to the adrenal glands (and indeed the kidneys themselves) are common, there are usually three arteries that supply each adrenal gland:
The superior suprarenal artery is provided by the inferior phrenic artery.
The middle suprarenal artery is provided by the abdominal aorta.
The inferior suprarenal artery is provided by the renal artery
• Venous drainage of the adrenal glands is achieved via the suprarenal veins:
The right suprarenal vein drains into the inferior vena cava.
The left suprarenal vein drains into the left renal vein or the left inferior phrenic vein
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Pharynx and Clinical Correlations BY Dr.Rabia Inam Gandapore.pptx
Adrenalgland
1. Physiology of the Adrenal GlandPhysiology of the Adrenal Gland
Adrenal cortex
-Anatomy review
-Synthesis of corticosteroids
-Glucocorticoids
-Mineralocorticoids
-Controlling system
-Renin-angiotensin system
Adrenal medulla and its hormones
-Synthesis and secretion
-Adrenergic receptors
-Physiologic effects
2. The adrenal glands are situated at the upper poles of each kidney
and consist of an outer cortex surrounding a central medulla
3. Adrenal cortex
•Has three histological zones
1. Zona glomerulosa (produces aldosterone, mineralocorticoid)
2. Zona fasciculata and
3. Zona reticularis (both produce glucocorticoids, cortisol and corticosterone) +
androgens (DHEA, DHEA sulfate)
•21 carbon atom compounds
- mineralocorticoid (aldosterone)
affects Na & K metabolism
- glucocorticoids (cortisol &
corticosterone) affect carbohydrate
and protein metabolism
•19 carbon atoms
- adrenal androgenes
4. •Synthesis of corticosteroids
Zona glomeruloza
Pregnenolone
Progesterone
11-Deoxycortico
sterone
Corticosterone
Aldosterone
Angiotensin II
(18-OH Corticosterone)
(2)
(3)
(4)
(5)
Cholesterol
Pregnenolone
Progesterone
11-Deoxycorticosterone
Corticosterone
17-OH
Pregnenolone DHEA
Androstene-
dione
(2)
(1)
17-OH
Progesterone
(2)
11-Deoxy-cortisol
Cortisol
(3)
(4)
(2)
(3)
(4)
Zona fasciculata and
zona reticularis
Hormone synthesis in the adrenal cortex. The zona glomerulosa can not convert corticosterone to
cortisol. 1-5 indicate the enzymes responsible for hormone synthesis: 1) 17α-hydroxylase (lacking in
zona glomerulosa); 2) 3 β-dehydrogenase; 3) 21 β-hydroxylase; 4) 11 β-hydroxylase; 5) corticosterone
methyloxidase
5. •Glucocorticoids
- cortisol ~ 96% is bound to corticosteroid-
binding globulin (CBG) or transcortin
- a minor degree of binding to albumin
- ~ 4% is free (biologically active)
- corticosterone (secreted 1/10th amount
of cortisol)
•Plasma level follows circadian rhythm:
- highest between 4.00 – 8.00 am
- levels secondary to variation in ACTH and circadian rhythm of CRF
7. •Antigrowth effects:
- growth hormone and its action on somatic growth
- cause muscle atrophy and muscle weakness
- Ca absorption from the gut
- collagen formation osteoporosis and delayed wound healing
•Anti-inflammatory and anti-allergic effects:
- capillary permeability
- leucocyte migration
- number of lymphocytes, monocytes, eosinophils, basophils and histamine
release
- number of neutrophils, erythrocytes and platelets
•Stress adaptation:
- activates the hypothalamic-hypophyseal-adrenal axis
- has some mineralocorticoid action – retain Na and water
- exerts negative feedback effect at the level of CRF and ACTH secretion
8. Effects of mineralocorticoidEffects of mineralocorticoid
•Is essential for life
•Aldosterone exerts ~95% of mineralocorticoid effect
•The majority of aldosterone remains bound:
- to albumin
- the rest is bound to CBG
•Na retention by:
- absorption of Na in distal and collecting tubules of nephrons
- sweat glands
- salivary glands and
- GI mucosa
• K elimination
•Maintains ECF (extracellular fluid volume)
9. Hypothalamic-hypophyseal-adrenal axis (control system)Hypothalamic-hypophyseal-adrenal axis (control system)
•CRF (hypothalamus) ACTH (adenohypophysis)
adrenal cortex (ZG & ZF) Cortisol
• Cortisol CRF ACTH cortisol (negative
feedback)
•CRH-ACTH axis is activated by:
- severe trauma - hemorrhage
- burns - heavy exercise
- pyrogens - infection and fever
- hypoglycemia - chemical intoxication
- histamine - pain
- electrical shock - surgery
- anxiety - cold exposure
•Level of “free” cortisol acts on anterior pituitary and hypothalamus
by negative feedback
11. Renin-angiotensin-aldosterone (control system)Renin-angiotensin-aldosterone (control system)
•Renin, a proteolytic enzyme, secreted by juxtaglomerular cells (JG) of the
juxtaglomerular apparatus (JGA)
•Baroreceptors and chemoreceptors of JGA are sensitive to:
- hypovolemia renin
- concentration of Na renin
•The renin-angiotensin system is also stimulated by:
- sympathetic nervous system renin
•Hypotension renin
•Aldosterone secretion is controlled by: ECF volume BP or Na
renin (JGA) angiotensin (plasma) angiotensin I
angiotensin II aldosterone (zona glomerulosa) [“converting enzyme”
converts ANG I to ANG II]
• K adrenal zona glomerulosa aldosterone
12.
13. Clinical
•Addison’s disease (due to destruction of adrenal gland – autoimmune disease/
tuberculosis) – primary hypoadrenalism
• ACTH melanocyte activity pigmentation of the skin + buccal mucosa
•Secondary hypoadrenalism is due to: ACTH (pituitary damage)
•Features:
- weakness - anorexia
- loss of weight - abdominal pain
- loss of Na and water dehydration - hypercalcemia
- hypotension - hyperkalemia metabolic acidosis
- postural dizziness - anemia
- hypoglycemia - lymphocytosis
- vomiting - eosinophilia
- diarrhea
15. Adrenal Medullary HormonesAdrenal Medullary Hormones
•Cells in the adrenal medulla synthesize and secrete
epinephrine and norepinephrine.
•The ratio of these two catecholamines
differs considerably among species:
in humans, cats and chickens, roughly 80, 60 and 30% of the
catecholamine output is epinephrine.
•Following release into blood, these hormones bind adrenergic
receptors on target cells, where they induce essentially the same
effects as direct sympathetic nervous stimulation
16.
17. Synthesis and Secretion of Catecholamines
Synthesis of catecholamines begins with the amino acid tyrosine, which is taken
up by chromaffin cells in the medulla and converted to norepinephrine and
epinephrine through the following steps:
Norepinephine and epinephrine are stored in electron-dense granules which also
contain ATP and several neuropeptides.
Secretion of these hormones is stimulated by acetylcholine release from preganglionic
sympathetic fibers innervating the medulla.
Many types of "stresses" stimulate such secretion, including exercise, hypoglycemia
and trauma. Following secretion into blood, the catecholamines bind loosely to and
are carried in the circulation by albumin and perhaps other serum proteins.
18. Adrenergic Receptors and Mechanism of Action
•The physiologic effects of epinephrine and norepinephrine are initiated by their
binding to adrenergic receptors on the surface of target cells.
•These receptors are prototypical examples of seven-pass transmembrane proteins
that are coupled to G proteins which stimulate or inhibit intracellular signalling
pathways.
19. Complex physiologic responses result from adrenal medullary stimulation because
there are multiple receptor types which are differentially expressed in different
tissues and cells.
The alpha and beta adrenergic receptors and their subtypes were
originally defined by differential binding of various agonists and antagnonists and,
more recently, by analysis of molecular clones.
Receptor Effectively Binds Effect of Ligand Binding
Alpha1 Epinephrine, Norepinphrine Increased free calcium
Alpha2 Epinephrine, Norepinphrine Decreased cyclic AMP
Beta1 Epinephrine, Norepinphrine Increased cyclic AMP
Beta2 Epinephrine Increased cyclic AMP
20. Physiologic Effects of Medullary Hormones
In general, circulating epinephrine and norepinephrine released from the
adrenal medulla have the same effects on target organs as direct stimulation
by sympathetic nerves, although their effect is longer lasting.
•Increased rate and force of contraction of the heart muscle: this is predominantly
an effect of epinephrine acting through beta receptors.
•Constriction of blood vessels: norepinephrine, in particular, causes widespread
vasoconstriction, resulting in increased resistance and hence arterial blood pressure.
•Dilation of bronchioles: assists in pulmonary ventilation.
•Stimulation of lipolysis in fat cells: this provides fatty acids for energy production
in many tissues and aids in conservation of dwindling reserves of blood glucose.
•Increased metabolic rate: oxygen consumption and heat production increase
throughout the body in response to epinephrine. Medullary hormones also promote
breakdown of glycogen in skeletal muscle to provide glucose for energy production.
•Dilation of the pupils.
•Inhibition of certain "non-essential" processes: an example is inhibition of
gastrointestinal secretion and motor activity.
Common stimuli for secretion of adrenomedullary hormones include exercise,
hypoglycemia, hemorrhage and emotional distress.