BIOS5130 Week 8 Slides

Week 8 Lecture Overview

Title: Human Physiology and Disease 2

Focus: Endocrine System Introduction

Instructor: Dr. Emma Hargreaves

Learning Outcomes

• Describe the structure and function of body systems: Gain a comprehensive understanding of how various body systems like the endocrine, nervous, and reproductive systems function individually and in concert.

• Understand integrated body systems and homeostasis: Explore the concept of homeostasis and how different systems work together to maintain a stable internal environment despite external changes.

• Link physiological malfunctions to diseases with examples: Discuss specific diseases and their correlation with physiological malfunctions, using case studies such as diabetes and hormonal imbalances.

• Appreciate the connections between physiology, anatomy, and medicine: Delve into how knowledge of anatomical structures enhances the understanding of physiological processes and clinical practices.

Module Convenor and Teachers

Convenor:Dr. Emma HargreavesEmail: e.j.mead@kent.ac.ukTeachers:Prof John DickinsonEmail: j.w.Dickinson@kent.ac.ukDr Sam SmithEmail: s.a.smith-75@kent.ac.ukDr Peter EllisEmail: P.J.I.Ellis@kent.ac.uk

Weekly Structure

Lecture Topics

• Week 8: Endocrinology

• Weeks 9-13: Nervous System

• Weeks 15-16: Kidneys

• Weeks 17-18: Muscles

• Week 19: Reproduction

Workshops

• Problem-solving practice sessions scheduled during Weeks 11 or 13, must be in groups for collaborative learning and application of knowledge.

Assessments

• Problem-solving Test in Week 15: An assessment to evaluate application of knowledge acquired during the course.

• 2-hour exam: Comprehensive exam covering all topics discussed throughout the module.

Feedback

• Week 16: Feedback will be provided for the problem-solving assessment, allowing students to understand areas of improvement and strengths.

Textbook

• Title: Human Physiology: An Integrated Approach

• Author: Dee Unglaub Silverthorn, 8th Edition

• Available in the library and as e-copies online for accessible reading materials.

Overview of Endocrinology Topics

• Hormone Classification: Detailed discussion on types, origins, functions, and potential target tissues of hormones.

• Endocrine Organs: Includes detailed descriptions of major endocrine glands such as the pituitary, thyroid, adrenal glands, and pancreas, focusing on their roles in bodily functions.

• Hormone Release Pathways: Insight into the mechanisms of hormonal release, including feedback loops and regulatory systems governing hormone levels.

• Endocrine Disorders: Examination of various endocrine disorders, their symptoms, and physiological underpinnings that lead to these conditions.

Hormone Basics

• Definition: A hormone is a specialized chemical messenger secreted into the bloodstream, designed to regulate specific bodily functions by targeting distant tissues.

• Mechanisms of Action: Hormones exert their effects through receptor binding on target cells, leading to specific cellular responses, which may include alterations in enzyme activity or gene expression for homeostasis.

• Concentration: Effective hormonal action occurs at exceedingly low concentrations, often in the nanomolar or picomolar range, underscoring their potency.

Types of Hormones

1. Peptide Hormones

   • Synthesized from inactive preprohormones with modifications post-translation.

   • Secreted via exocytosis into the bloodstream.

2. Steroid Hormones

   • Derived from cholesterol and known to bind to intracellular receptors.

   • Require carrier proteins for effective transport in the bloodstream.

3. Amine Hormones

   • Synthesized from the amino acid tyrosine (e.g., catecholamines such as adrenaline) and can exhibit properties of both peptide and steroid hormones depending on their structure.

Hormone Interactions

• Synergistic Effects: Combined actions of hormones may produce a greater effect than individual actions alone (e.g., glucagon and cortisol together increase blood glucose levels).

• Permissive Effects: One hormone may enhance the action of another, enabling more pronounced physiological effects (e.g., thyroid hormones enhance gonadotropin effects).

• Antagonistic Effects: Hormones may oppose each other's actions, regulating bodily functions in a balance (e.g., insulin lowers blood glucose while glucagon increases it).

Endocrine Disorders

Causes

• Hormone Excess: Conditions such as acromegaly due to excess growth hormone or Graves' disease involving hyperthyroidism.

• Hormone Deficiency: Examples include pituitary dwarfism due to insufficient growth hormone or Addison's disease from adrenal insufficiency.

• Receptor Defects: Conditions like pseudohypoparathyroidism arise from dysfunctional hormone receptor signaling.

Case Study: Graves' Disease

• Symptoms: Patients often exhibit irritability, significant weight loss, rapid heart rate (palpitations), and a visible goitre.

• Treatment Options: Therapies may include antithyroid medications to inhibit thyroid hormone production, radioactive iodine treatment to ablate overactive thyroid tissue, or surgical removal in severe cases.

Knowledge Checks and Exam Preparation

• Thorough understanding of hormone action pathways, including synthesis, release, and mechanism of action essential for identifying mechanisms of endocrine disorders.

• Familiarize yourself with feedback loops (positive and negative feedback) in maintaining homeostasis and their implications in health and disease.

• Review physiological mechanisms of key hormones and clinical correlations with various endocrine disorders for comprehensive exam preparation.

Important Concepts

• Role of Hypothalamus: It serves as a crucial regulatory center for the endocrine system, orchestrating hormonal signals to the pituitary gland.

• Feedback Mechanisms: Understand the feedback mechanisms in the hypothalamic-pituitary axis which regulate hormonal homeostasis.

• Application of Knowledge: Emphasize how physiological knowledge can be applied in clinical diagnosis and treatment planning for endocrine disorders.