Medical Physiology for Dentistry 1st Year

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Questions and Answers

What primarily makes up the extravascular fluid?

Blood plasma

Intracellular fluid

Lymphatic fluid

Interstitial fluid and transcellular fluids (correct)

Which function of body water helps regulate body temperature?

Heat absorption, distribution, and evaporation (correct)

Lubricant in joints

Ionizing medium

Chemical and enzymatic reactions

Which anion is predominantly found in extracellular fluid (ECF) compared to intracellular fluid (ICF)?

Cl- (correct)

HPO4

HCO3

SO4

What is NOT a function of body water?

Increases blood pressure Signup and view all the answers

What is the primary role of the cell membrane?

Protect the cell and provide selective permeability Signup and view all the answers

Which of the following is least abundant in intracellular fluid (ICF)?

Na+ Signup and view all the answers

What is the relationship between charge and diffusion?

Opposite charges attract and enhance diffusion. Signup and view all the answers

What property is characteristic of facilitated diffusion?

Involves a carrier protein. Signup and view all the answers

Which of the following correctly describes the composition of normal extracellular fluid (ECF)?

Contains mainly Na+ and Cl- Signup and view all the answers

What is the primary function of red blood corpuscles (RBCs)?

Transport oxygen Signup and view all the answers

What type of fluids are included in transcellular fluids?

Cerebrospinal and intraocular fluid Signup and view all the answers

What is the primary mechanism of osmosis?

Movement of solvent from high to low concentration. Signup and view all the answers

Which of the following is NOT a function of blood?

Energy production Signup and view all the answers

What is the average concentration of albumin in blood plasma?

4 gm/100 ml Signup and view all the answers

How is osmotic pressure primarily determined?

By the number of particles per unit volume. Signup and view all the answers

Which of these components constitutes the majority of plasma?

Water Signup and view all the answers

What substance is typically transported by carriers in facilitated diffusion?

Glucose Signup and view all the answers

Leukopenia refers to a decrease in which type of blood cell?

White blood cells Signup and view all the answers

Which statement correctly describes a unique feature of osmosis?

It only involves solvent molecules like water. Signup and view all the answers

What is the main role of plasma proteins?

Maintaining osmotic pressure Signup and view all the answers

What role does insulin play in facilitated diffusion?

It regulates the number of glucose carriers. Signup and view all the answers

What unit is used to measure osmosis?

Osmole Signup and view all the answers

What happens to blood volume during dehydration?

Decreases Signup and view all the answers

Which type of blood cells are primarily responsible for the body's immune response?

White blood cells Signup and view all the answers

What is the primary storage form of iron in the body?

Ferritin Signup and view all the answers

Which vitamin is essential for nuclear maturation and cell division?

Vitamin B12 Signup and view all the answers

What substance helps protect vitamin B12 from digestion and facilitates its absorption?

Intrinsic factor Signup and view all the answers

What role does transferrin play in the body?

It forms a part of hemoglobin in red blood cells. Signup and view all the answers

Which factor negatively affects iron absorption in the diet?

Oxalates and phytic acids Signup and view all the answers

Where is excess iron primarily deposited in the body?

Liver hepatocytes Signup and view all the answers

What is the role of Vitamin C in relation to iron?

It facilitates iron absorption. Signup and view all the answers

Which trace elements act as cofactors for hemoglobin formation?

Copper and cobalt Signup and view all the answers

What is the primary source of erythropoietin in the body?

Kidney Signup and view all the answers

Which organ acts as an extramedullary site for erythropoiesis?

Liver Signup and view all the answers

Which condition primarily stimulates the secretion of erythropoietin?

Hypoxia Signup and view all the answers

Which vitamin is essential for the absorption of vitamin B12 in the stomach?

Intrinsic factor Signup and view all the answers

What is the normal hemoglobin concentration in adult males?

15 gm/100 mL blood Signup and view all the answers

What type of anemia is characterized by excessive hemolysis of red blood cells?

Normocytic Normochromic anemia Signup and view all the answers

Which organ is primarily responsible for converting ferric iron to ferrous iron?

Stomach Signup and view all the answers

What effect does anemia have on the heart?

Leads to faster heart rate Signup and view all the answers

What is the average lifespan of platelets?

7-12 days Signup and view all the answers

What is the primary role of platelets in hemostasis?

Formation of a platelet plug Signup and view all the answers

What triggers the initial vasoconstriction during hemostasis?

Local myogenic contraction and pain reflex Signup and view all the answers

Which factor plays a key role in platelet adhesion to the injured blood vessel?

Von Willebrand factor Signup and view all the answers

What substance is released by activated platelets to promote aggregation?

Thromboxane A2 Signup and view all the answers

During which step of hemostasis is fibrin formation critical?

Stabilization of platelet plug Signup and view all the answers

Which of the following is not a function of platelets in hemostasis?

Production of red blood cells Signup and view all the answers

What is the final step in the hemostatic response?

Repair of the injured blood vessel Signup and view all the answers

Study Notes

Medical Physiology for Dentistry Students

Course Title: Medical Physiology
Course Description: General and Blood Physiology
Course Level: 1st Year Dentistry
Course Code: GPΗΜ-11
Instructor: Dr/ Elshymaa Abdel-Hady Abdel-Hakeem
Department: Medical Physiology Department
University: Minia University

Introduction to Human Physiology

Physiology is the study of the functions of the human body.
It's divided into two parts: Physio (meaning function) and Logy (meaning science).
Human physiology examines how the body works under different internal and external conditions to maintain life.

Organization of the Human Body

The cell: The basic living unit of the body.
The tissue: Groups of cells with the same shape and function, arranged side by side.
The organ: Composed of multiple tissues with a specific function. (e.g., stomach digests, kidney excretes).
The system: A group of organs working together with complementary functions to carry out a particular role. Different systems work together to maintain life.
Different systems of the human body: Endocrine, nervous, cardiovascular, respiratory, digestive, excretory, reproductive, musculoskeletal.

Human Body Composition

Water: 60% of body weight in young adult males.
Solids: 40% consisting of a) organic (proteins 18%, fats 15%), and b) inorganic (minerals 7%).
Intracellular fluid (ICF): About 40% of body weight (approximately 28 liters in a 70kg male).
Extracellular fluid (ECF): About 20% of body weight (approximately 14 liters in a 70kg male). ECF includes:
- Intravascular fluid: Plasma (about 1/4 of ECF volume).
- Extravascular fluid: Interstitial fluid in spaces between cells (about 3/4 of ECF volume).
Transcellular fluids: Fluids in closed spaces lined by epithelium (e.g., cerebrospinal fluid, intraocular fluids).

Functions of Body Water

Medium for chemical and enzymatic reactions.
Enables physical processes like diffusion and filtration.
Regulates pH and body fluid osmolarity.
Regulates body temperature.
Lubricant for joints and cavities (e.g., pleura).
Refractive medium in the eye.
Protects the brain (cerebrospinal fluid).
Facilitates oxygen and carbon dioxide exchange (lungs and tissues).

Normal Composition of ECF and ICF

Data presented in a table comparing electrolytes and other components of ECF and ICF.

The Human Cell (Structure)

The cell membrane.
The nucleus.
The cytoplasm (including organelles):
- Membranous: Endoplasmic reticulum, mitochondria, lysosomes, Golgi apparatus.
- Non-membranous: Ribosomes, centrosome.

The Cell Membrane (Structure and Function)

Formed by phospholipids
- Phospholipid bilayer: Hydrophilic heads facing outwards and inwards, hydrophobic tails in the middle.
Contains proteins
- Peripheral proteins: On the surfaces.
- Transmembrane proteins: Through the membrane.
Functions:
- Forms a boundary.
- Selectively permeable.

Functions of Cell Membrane Proteins

Receptors: Binding sites for hormones and other signaling molecules.
Pumps: Active transport of substances against concentration gradients (e.g., sodium-potassium pump).
Enzymes: Catalyzing reactions on the cell surface or within the membrane.
Carriers (Transport proteins): Facilitating movement of substances across the membrane.
- Uniport: Transports one substance in one direction.
- Symport: Transports two or more substances together, same direction.
- Antiport: Transports two substances together in opposite directions.
Channels: Allowing passage of specific substances (e.g., ions).
- Non-gated channels: Always open.
- Gated channels: Open or close in response to stimuli (e.g., voltage-gated, ligand-gated, mechanically-gated).

Transport Mechanisms Through Cell Membranes

Passive transport: No energy required.
- Diffusion: Free movement of substances from high to low concentration.
- Osmosis: Diffusion of water across a selectively permeable membrane.
- Filtration: Movement of fluid across a membrane due to pressure differences.
- Facilitated diffusion: Passive transport with help of carrier proteins.
Active transport: Needs energy (ATP).
- Primary active transport: ATP directly used to transport substance.
- Secondary active transport: Transport against its gradient utilizing the electrochemical gradient of another substance.

Other Transport Processes

Bulk transport (i.e., Endocytosis and Exocytosis): Used for large molecules.

The Blood Composition

Plasma: 55% of blood volume, consists mainly of water, proteins, and other solutes.
Blood cells: 45% of blood volume, consisting of red blood cells (RBCs), white blood cells (WBCs), and platelets (thrombocytes).

Functions of Blood and Blood Cells

Transport of oxygen, carbon dioxide, nutrients, waste products, and hormones.
Defence.
Hemostasis (stops bleeding).
Maintaining homeostasis (internal balance of body).

Blood Proteins:

Albumin: Maintains osmotic pressure, transports substances.
Globulins: Defensive functions (antibodies).
Fibrinogen: Blood clotting.
Prothrombin: Blood clotting.

Red Blood Cells (Erythrocytes)

Structure: Biconcave discs, no nucleus, contain hemoglobin.
Function: Carry oxygen and carbon dioxide.
Formation: Erythropoiesis in bone marrow.
Regulation: Controlled by erythropoietin hormone (released by the kidneys, stimulated by low oxygen levels).

White Blood Cells (Leukocytes)

Types: Granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (monocytes, lymphocytes).
Function: Immune system (defence against infections).

Platelets (Thrombocytes)

Structure: Small, non-nucleated cell fragments.
Function: Crucial for blood clotting (hemostasis).

Blood Coagulation

Intrinsic pathway: Activated by factors within the blood itself.
Extrinsic pathway: Activated by factors outside the blood (e.g., tissue damage).
Common pathway: Converges from both pathways to form a blood clot.

Regulation of Blood Coagulation

Physiological mechanisms limit coagulation to prevent unnecessary clotting.
Inactivation of active coagulation factors.
Fibrinolysis (breakdown of fibrin).
Vitamin K and calcium are essential for the coagulation factors, deficiency leads to bleeding disorders.

Diseases of blood

Anemia: Reduced RBCs or haemoglobin content, causes include incompatible blood transfusions, snake venom, infections (like malaria), and chemical toxins.
polycythemia: abnormally high concentration of RBCs or their haemoglobin content, can be caused from issues such as bone marrow cancers.

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Test your knowledge on Medical Physiology tailored for 1st-year dentistry students. This quiz covers general and blood physiology, as well as the fundamental organization of the human body. Explore the roles of cells, tissues, organs, and systems in human health.