Essential Physiology for Dental Students

Kamran Ali, Elizabeth Prabhakar, Kamran Ali, Elizabeth Prabhakar

• Publisher: Wiley-Blackwell
• Year: 2018
• Print ISBN:
  9781119271710
• eBook ISBN:
  9781119271758
• Edition: 1
• Topic: Medicine
• Subtopic: Dentistry

Essential Physiology for Dental Students offers comprehensive information on human physiology, tailored to the needs of students of dentistry. This new addition to the Dentistry Essentials series helps students gain a deeper understanding of how physiological concepts apply to clinical dental practice. Each chapter outlines an organ system in sufficient detail whilst emphasizing its relevance to clinical dentistry. Written in a student-friendly style, it contextualizes how normal and altered physiology affects dental care and highlights the implications of dental interventions on the body's functioning. 

Essential Physiology for Dental Students provides readers with complete coverage of: cell physiology; nerve and muscle physiology; the cardiovascular system; the respiratory system; the gastro-intestinal system; the renal system; haematology; endocrinology including the regulation of blood glucose and blood calcium; and the central nervous system. 

• Covers each system in detail, while emphasizing the relevance to dental students
• Presented using a reader-friendly layout with illustrations and clinical photographs throughout
• Features interactive MCQs and EMQs and downloadable images on a companion website

Essential Physiology for Dental Students is an excellent resource for undergraduate dentistry students, dental hygiene and therapy students, and dental nursing students.  It also greatly benefits newly qualified dentists preparing for postgraduate examinations such as MFDS, LDS, ORE, and also the US National Boards.

PART I
Introduction

CHAPTER 1
The Cell: Structure and Function

Vehid Salih and Kamran Ali

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Key Topics

• Overview of different types of living organisms
• Organisation of the human body
• Components of human cells
• Regeneration and repair

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Learning Objectives

To demonstrate an understanding of the:

• Differences between prokaryotes and eukaryotes
• Structure and functions of the cell organelles
• Relevance of regeneration and repair to oral and dental tissues
• Potential applications of stem cells

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Introduction

A cell is the fundamental structural, functional, and biological unit of all known living organisms (except viruses). Individual cells range from 1 to 100 μm and are visible only under a microscope as the human eye is unable to see anything smaller than 100 μm. Living organisms are described as unicellular (microorganisms) or multicellular (e.g. plants and animals). Unicellular organisms are also classified as prokaryotes and multicellular organisms as eukaryotes. Prokaryotes lack a nucleus and cytoplasmic organelles and are represented by bacteria. Eukaryotes have a nucleus as well as cytoplasmic organelles and include microorganisms such as fungi, protozoa, algae as well as animals and humans. Nevertheless, both types possess a cell membrane and contain deoxyribonucleic acid (DNA). Viruses are neither prokaryotes nor eukaryotes as they lack characteristics of living organisms, apart from the ability to replicate. They are best regarded as obligate parasites as they can only replicate in living cells.

An adult human body comprises approximately 75–100 trillion cells, and more than 200 varieties of specialised cells have already been identified. The cells in the human body join to form tissues. Four basic human tissues include epithelium, connective tissue, nervous tissue, and muscle. Different tissues are grouped to form organs which in turn join to form various systems of the human body. The function of the human body is maintained by thousands of control systems at the level of cells, tissues, organs as well as systems allowing the body to maintain a constant internal environment, or homeostasis. Nevertheless, all physiological processes as well as disease mechanisms can be described at, and ascribed to, the cellular level. Cells are diverse and vary tremendously in their morphology and function. Figure 1.1 shows the main features of a typical human cell.

Figure 1.1 Components of a cell.

Source: Tortora and Derrickson (2013).

Components of the Human Cell

Cell Membrane

The cell membrane (plasmalemma) forms the outer boundary of the cell. The selective permeability of the cell membrane allows the cell to interact with its environment in a controlled way. The cell membrane is composed of a fluid combination of lipids (phospholipids and cholesterol), proteins and a small amount of carbohydrates. The basic structure of the cell membrane is formed by a phospholipid bilayer (Figure 1.2). The hydrophilic head region of the phospholipids faces the exterior (extracellular fluid or interstitial or tissue fluid) or aqueous interior (intracellular fluid or cytoplasmic face) of the cell, while the hydrophobic tails remain isolated. A variety of proteins attach to the surface of the phospholipid bilayer, while others traverse it partly or completely. The membrane proteins perform a variety of roles including: channel proteins, which facilitate passive transport across the cell membrane; protein pumps for active transport (Chapter 2); and receptor proteins for hormones and other endogenous as well as exogenous chemicals. Carbohydrates are either found in combination with proteins (glycoproteins) or lipids (glycolipids) and function as recognition markers, allowing the immune system to differentiate ‘self’ from foreign cells.

Figure 1.2 Fluid mosaic model of plasma membrane.

Source: Tortora and Derrickson (2013).

Nucleus

The nucleus is a double membrane‐bound structure and measures approximately 3–14 μm in most cells. It stores the DNA and associated proteins (= chromatin) in the form of chromosomes. The nuclear membrane (nucleolemma) isolates the DNA from the cytoplasm and is continuous with the endoplasmic reticulum (Figure 1.1). The nucleolemma contains pores to allow passage of messenger RNA (mRNA) units of nucleic acid. The gel‐like portion of the nucleus is known as nucleoplasm. Within the nucleus, proteins, DNA, and ribonucleic acid (RNA) are concentrated around specific chromosomal regions to form the nucleolus (plural: nucleoli). The nucleolus itself is not bound by a membrane and is responsible for synthesis of ribosomes.

The functions of the cell are coded in the genes. The genetic code or nucleotide sequence of DNA in the genes is used to direct protein synthesis, a process known as gene expression. First, the DNA is used as a template to link nucleotides, forming a strand of an mRNA molecule. This process is referred to as transcription and is facilitated by the enzyme RNA polymerase. The mRNA is then transferred across the nucleolemma into the cytoplasm and is used as a template by ribosomes to synthesise proteins, a process referred to as translation. Further processing of the proteins such as addition of phosphate (phosphorylation) or carbohydrates (glycosylation) takes place through a process known as post‐translation modification.

The nucleus is present in all cells of the body, excluding red blood cells and platelets. Liver cells (hepatocytes) can have one or two nuclei, while the osteoclasts and skeletal ...

Table of contents

• Cover
• Table of Contents
• Preface
• PART I: Introduction
• PART II: Nerve Muscle Physiology
• PART III: Cardiovascular System
• PART IV: Respiratory System
• PART V: Gastrointestinal System (GIT)
• PART VI: Hepato Renal System
• PART VII: Blood
• PART VIII: Endocrinology
• PART IX: Nervous System
• Index
• End User License Agreement