Introduction to Physiology: Body Water & Homeostasis

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of adrenergic receptor is primarily found in the organs innervated by the sympathetic system?

Alpha (α) receptors (correct)

Beta (β) receptors (correct)

Muscarinic receptors

Nicotinic receptors

What is the primary neurotransmitter that activates muscarinic receptors in the parasympathetic system?

Dopamine

Acetylcholine (correct)

Noradrenaline

Serotonin

Which statement correctly describes the origin of preganglionic fibers in the sympathetic nervous system?

Thoracic and lumbar regions (correct)

Sacral region only

Cervical region

Cranio-Sacral region

What type of ganglia do postganglionic fibers of the sympathetic system typically originate from?

Collateral ganglia Signup and view all the answers

How do the types of fibers compare between the sympathetic and parasympathetic systems?

Parasympathetic system has long cholinergic preganglionic and short cholinergic postganglionic fibers. Signup and view all the answers

Which of the following correctly describes the study of physiology?

The study of normal body functions. Signup and view all the answers

What percentage of total body weight is represented by water in an adult male?

60% Signup and view all the answers

Which factor does NOT affect total body water?

Amount of muscle mass Signup and view all the answers

What is the primary cation found in extracellular fluid (ECF)?

Na+ Signup and view all the answers

Which component of extracellular fluid makes up 3/4 of its total volume?

Interstitial fluid (ISF) Signup and view all the answers

In the context of body fluid composition, what is a major difference between intracellular fluid (ICF) and extracellular fluid (ECF)?

ICF has higher protein concentration than ECF. Signup and view all the answers

What is the primary anion present in extracellular fluid (ECF)?

Chloride Signup and view all the answers

Which statement accurately reflects the factors affecting water balance in the body?

Obesity is associated with decreased water content. Signup and view all the answers

What is the primary effect of the contraction of tarsal muscles?

Increased palpebral fissure width Signup and view all the answers

What does the contraction of the ciliary muscle achieve?

Increased lens power for near vision Signup and view all the answers

Which nerve is responsible for the secretion of profuse watery saliva?

Facial nerve Signup and view all the answers

What effect does the vagus nerve have on the heart?

Inhibits heart properties, decreasing heart rate Signup and view all the answers

What effect does the sympathetic nervous system have on the urinary bladder?

Inhibits wall contraction and contracts internal sphincter Signup and view all the answers

What is the primary function of erythrocytes?

Transportation of gases and nutrients Signup and view all the answers

Which component makes up approximately 55% of blood volume?

Plasma Signup and view all the answers

What is the clinical significance of hematocrit levels?

It reflects the percentage of red blood cells in total blood volume. Signup and view all the answers

Which of the following statements regarding the sympathetic nervous system is true?

It causes vasoconstriction of visceral blood vessels. Signup and view all the answers

Which nerves have sacral outflow in the parasympathetic nervous system?

S2–S4 Signup and view all the answers

What happens during the relaxation of walls in the stomach and intestines?

Retention of food Signup and view all the answers

What percentage of the blood volume do thrombocytes account for?

Less than 1% Signup and view all the answers

What is the composition of plasma?

90% water, 9% inorganic constituents Signup and view all the answers

Which blood group has no agglutinins in the plasma?

AB Signup and view all the answers

What initiates vascular spasms during the hemostatic process?

Nervous activity and chemical release Signup and view all the answers

What is the correct sequence of events in blood coagulation?

Prothrombin activator -> Thrombin -> Fibrin Signup and view all the answers

In which type of sympathetic ganglia is the relay of preganglionic sympathetic fibers found?

Lateral ganglia Signup and view all the answers

What type of neurotransmitter is released by sympathetic post-ganglionic neurons?

Noradrenaline Signup and view all the answers

How does the body prevent excessive clotting and bleeding?

By balancing coagulation and fibrinolysis Signup and view all the answers

Which type of ganglia is found near or on the wall of effector organs?

Terminal ganglia Signup and view all the answers

What role does von Willebrand factor play in the platelet plug formation?

Facilitates platelet adherence to collagen Signup and view all the answers

Rh+ve individuals possess which type of agglutinogen on their red blood cells?

D Signup and view all the answers

In hemostasis, which step follows the formation of a platelet plug?

Blood coagulation Signup and view all the answers

Which system in the autonomic nervous system releases acetylcholine?

Cholinergic system Signup and view all the answers

What is the primary function of autonomic ganglia?

Relay and distribution of nerve signals Signup and view all the answers

Excess fibrinolysis can lead to which condition?

Hemorrhage Signup and view all the answers

What occurs during fibrinolysis?

Breakdown of fibrin Signup and view all the answers

Which of the following best describes the composition of intracellular fluid (ICF)?

High in potassium and phosphates with a small amount of sodium. Signup and view all the answers

What is the primary consequence when water loss exceeds water gain?

Dehydration. Signup and view all the answers

Which of the following is NOT a factor that must be maintained for homeostasis?

Blood volume of 10 L. Signup and view all the answers

Which body system is primarily responsible for the movement of blood and thus contributes to homeostasis?

Circulatory system. Signup and view all the answers

What is the role of the kidneys in maintaining homeostasis?

Remove wastes and excess water from the blood. Signup and view all the answers

Which part of the autonomic nervous system is responsible for initiating the fight-or-flight response?

Sympathetic nervous system. Signup and view all the answers

The effector organ of the somatic nervous system is primarily which of the following?

Skeletal muscle. Signup and view all the answers

Which structure in the body serves as an outer protective barrier?

The skin. Signup and view all the answers

What is a significant risk associated with homeostasis failure?

Onset of diseases. Signup and view all the answers

Which division of the autonomic nervous system originates from the thoracolumbar region?

Sympathetic nervous system. Signup and view all the answers

Which of the following best describes the autonomic nervous system?

Regulates visceral functions automatically. Signup and view all the answers

Which physiological parameter represents the standard pH level in a healthy human body?

7.4. Signup and view all the answers

What is the main role of the endocrine system in homeostasis?

To regulate cellular functions through hormones. Signup and view all the answers

Which of these systems in the body is primarily responsible for gas exchange?

Respiratory system. Signup and view all the answers

Which plasma protein is primarily responsible for maintaining osmotic pressure in the blood?

Albumin Signup and view all the answers

What is the primary function of fibrinogen in blood physiology?

Formation of blood clots Signup and view all the answers

Which cells are classified as granulocytes in the leukocyte population?

Neutrophils, Eosinophils, Basophils Signup and view all the answers

What factor contributes to the stimulation of erythropoiesis during decreased oxygen supply?

Elevated erythropoietin hormone release Signup and view all the answers

What is the life span of red blood cells in circulation?

120 days Signup and view all the answers

What role does Vitamin B12 play in the context of red blood cell maturation?

It assists in RBC maturation. Signup and view all the answers

Which white blood cell type is primarily involved in the destruction of parasitic worms?

Eosinophils Signup and view all the answers

What component is essential for hemoglobin synthesis in red blood cells?

Iron Signup and view all the answers

What percentage of leukocytes are neutrophils?

40%-70% Signup and view all the answers

What is the primary role of the lymphocytes in the immune response?

Mount immune response via cell attack or antibodies Signup and view all the answers

Which blood group system includes antigens A and B?

ABO system Signup and view all the answers

What condition results from a decrease of red blood cells or hemoglobin concentration?

Anemia Signup and view all the answers

What is the primary function of basophils in the immune system?

Release histamine and induce inflammation Signup and view all the answers

What is the role of the liver in erythropoiesis?

Forms globin and secretes erythropoietin Signup and view all the answers

Study Notes

Introduction to Physiology: Total Body Water & Homeostasis

Physiology is the study of normal body functions, specifically the normal functions of a living organism.
The cell is the basic structural and functional unit of living matter.
In an adult male (70 kg):
- 18% of body weight is protein
- 15% of body weight is fat
- 7% of body weight is minerals
- 60% of body weight is water

Factors Affecting Total Body Water

Physiological factors:
- Fat: Water content decreases with obesity.
- Sex: Females have lower water content than males.
- Age: Total body water decreases with age.

Distribution of Body Water

Intracellular fluid (ICF): 2/3 of total body water; inside cells.
Extracellular fluid (ECF): 1/3 of total body water; outside cells.
- Interstitial Fluid (ISF): 3/4 of ECF
- Plasma: 1/4 of ECF

Composition of Body Fluids

ICF and ECF differ significantly in composition.
ECF: High Na⁺, low K⁺; main cation is Na⁺, High Cl⁻, low phosphates & proteins; main anion is Cl⁻.
ICF: High K⁺, low Na⁺; main cation is K⁺, High phosphates & proteins, low Cl⁻; main anions are phosphates & proteins

Water Balance

Water gain: Drinking, food, metabolism.
Water loss: Urine, respiration, skin, stool.
Balanced state: Water gain = water loss.
Dehydration: Water loss > water gain.
Overhydration: Water gain > water loss.

Homeostasis

Homeostasis is the maintenance of constant conditions in the internal environment (ECF).
This constancy is crucial for normal cell function.

Advantages of Homeostasis

Increased survival chances.
Ability to live in diverse environments.
Proper brain function.

Factors Maintained Through Homeostasis

pH: 7.4
Blood volume: 5 liters
Blood pressure: 120/80 mmHg
Temperature: 37°C

Body Systems and Homeostasis

Circulatory system: Keeps blood moving.
Respiratory system: Oxygen uptake/CO₂ release.
Musculoskeletal system: Movement and protection.
Nervous system: Control of movement.
Endocrine system: Hormonal regulation.
Digestive system: Nutrient absorption.
Kidneys/Urinary system: Waste removal/water balance.
Immune system: Defense from foreign substances.
Skin: Outer protection
Reproductive: Offspring production.

Autonomic Nervous System 1

The nervous system is the master control and communication system of the body, transmitting impulses to every organ.
The peripheral nervous system has somatic and autonomic divisions.
Somatic: effector organ = skeletal muscle.
Autonomic: effector organ = cardiac muscle, smooth muscle, glands.

Autonomic NS 1 (cont.)

Autonomic nervous system (ANS) regulates visceral functions. It is the involuntary nervous system.
Divisions of ANS: sympathetic and parasympathetic.
- Sympathetic (thoracolumbar): Originates from the thoracic and lumbar regions of the spinal cord.
- Parasympathetic (craniosacral): Originates from the cranial nerves (III, VII, IX, X) and sacral regions of the spinal cord.

Autonomic NS 1: Sympathetic Functions

Cervical division:
- Eye: pupil dilation, eyelid widening, distant vision
- Salivary glands: viscous saliva secretion
- Skin: Vasoconstriction, sweat secretion, hair erection
Cardiopulmonary division:
- Heart: increased rate, contractility, conductivity and excitability
Splanchnic division:
- Stomach/intestines: decreased motility, secretion and food retention
- Liver: glycogenolysis, lipolysis
Pelvic division:
- Bladder: urine retention
- Rectum: feces retention

Autonomic NS 1: Parasympathetic Functions

Cranial outflow:
- Oculomotor (III): pupil constriction, near vision
- Facial (VII): watery saliva secretion
- Glossopharyngeal (IX): saliva, posterior tongue glands
- Vagus (X): heart rate decrease, decreased contractility, bronchoconstriction, digestive tract activity
Sacral outflow:
- Bladder: urination
- Rectum: defecation

Blood Physiology

Blood is a liquid connective tissue, comprising plasma (55%) and blood cells (45%)—red blood cells (RBCs), white blood cells (WBCs), and platelets.
Average blood volume in a 70 kg male is 5-6 liters.
Hematocrit (PCV) is the percentage of RBCs in the total blood volume.

Blood Functions

Transport: Gases, nutrients, hormones, waste products.
Regulation: Acid-base balance, blood pressure.
Defense: Against infection (WBCs, immune system).
Hemostasis: Stopping bleeding (platelets and clotting factors).

Blood Plasma

Plasma is 90% water, with proteins (albumin, globulins, fibrinogen, prothrombin), inorganic substances, and blood gases.
Plasma minus clotting factors is serum.
Albumin: Maintains osmotic pressure, transports smaller molecules.
Globulins: Transport hormones/fat-soluble vitamins, antibodies.
Fibrinogen: Forms blood clots.
Prothrombin: Blood clotting.

White Blood Cells (Leukocytes)

Granulocytes: Contain granules; neutrophils (bacteria phagocytosis), eosinophils (parasites), basophils (inflammation mediators).
Agranulocytes: Lack granules; lymphocytes (immunity), monocytes (phagocytosis, macrophages).
Chemotheraphy effects Leukopenia, as it kills fast-growing cells, including many WBCs and other cells.

Red Blood Cells (Erythrocytes)

Biconcave disc shape for gas exchange, flexible for capillary passage.
Packed with hemoglobin (Hb) for oxygen/carbon dioxide transport.
No nucleus or mitochondria.
Hemoglobin: Consists of four protein chains (globins) and four heme groups. Heme: nonprotein group that binds oxygen.
Functions: Carry hemoglobin, transport oxygen, transport carbon dioxide, buffers pH
Counts: Males (4.8-5.8 million/mm³), Females (4.2-5.2 million/mm³)
Lifespan: 120 days
Erythropoiesis: RBC production.
- Sites in utero: Liver, spleen
- Sites after birth:
  - Infants/children: Red bone marrow of axial and appendicular skeleton
  - Adults: Red bone marrow of axial skeleton primarily

Erythropoiesis Regulation

Hypoxia: Low oxygen supply stimulates erythropoiesis by triggering erythropoietin (EPO) hormone release from kidneys primarily and from liver .
Role of nutrients: Cobalamin (Vit B12), folic acid, vitamin B6, amino acids, vitamin C, and iron are crucial for Hb synthesis and RBC maturation.

Blood Groups

ABO system: A, B, AB, and O blood groups. Based on the presence/absence of A and B antigens on RBC surfaces and corresponding antibodies in the plasma (α vs β).
Rh system: Rh+ve (presence of D antigen) and Rh-ve (absence).
Rh incompatibility (in pregnancy): Maternal Rh− blood interacting with fetal Rh+ blood can cause complications in subsequent pregnancies.

Hemostasis

Hemostasis is the process of stopping bleeding, keeping blood in damaged vessels.
Stages:
- Vascular spasm: Damaged blood vessels constrict.
- Platelet plug formation: Platelets adhere to collagen, release chemicals to attract more platelets.
- Coagulation: Complex cascade forming a fibrin mesh.
Fibrinolysis: Breakdown of clot to prevent blockages (by enzymes like plasmin).
Anticoagulants: Prevent clots within blood vessels.

Autonomic Nervous System 2

Autonomic Ganglia: Collections of neurons outside CNS, relaying preganglionic neurons to postganglionic neurons.
- Types:
  - Lateral (paravertebral): Sympathetic only
  - Collateral: Sympathetic and parasympathetic, primarily sympathetic
  - Terminal: Parasympathetic only
Chemical Transmission in ANS: Neurotransmitters (ACh and norepinephrine) mediate transmission between neurons and effector organs.
Chemical Divisions:
- Cholinergic systems: ACh release (preganglionic, some postganglionic)
- Noradrenergic systems: Norepinephrine release (most postganglionic sympathetic)
Types of receptors:
- ACh (cholinergic): Nicotinic (ganglia) and muscarinic (most parasympathetic)
- Norepinephrine (noradrenaline): Alpha and beta adrenergic (most sympathetic)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fundamentals of physiology with a focus on total body water and homeostasis. This quiz covers the distribution of body fluids, factors affecting total body water, and the composition differences between intracellular and extracellular fluids. Test your knowledge on how these elements work together to maintain normal body functions.