The pericardium is a double-walled membranous sac that encloses the heart and contains pericardial fluid, which reduces friction during heartbeats and protects the heart from mechanical injury.
Topics
Reproduction in Lower and Higher Plants
- Reproduction
- Asexual Reproduction
- Asexual Reproduction in Unicellular Organisms > Binary Fission
- Binary Fission > Simple Binary Fission
- Binary Fission > Transverse Binary Fission
- Binary Fission > Longitudinal Binary Fission
- Asexual Reproduction in Unicellular Organisms > Multiple Fission
- Asexual Reproduction in Unicellular Organisms > Budding
- Asexual Reproduction in Multicellular Organisms > Fragmentation
- Asexual Reproduction in Multicellular Organisms > Spore Formation
- Vegetative Reproduction or Vegetative Propagation
- Natural Vegetative Propagation
- Artificial Vegetative Propagation
- Sexual Reproduction
- Flower - a Fascinating Organ of Angiosperms
- Structure and Development of Anther
- Microsporogenesis
- Structure and Development of Male Gametophyte
- Structure and Development of Ovule
- Types of Ovules (Based on Orientation)
- Types of Ovules (Based on Integuments)
- Megasporogenesis
- Development of Female Gametophyte or Embryo Sac
- Pollination
- Autogamy
- Cross-pollination
- Geitonogamy
- Agents and Types of Cross-pollination
- Anemophily
- Hydrophily
- Entomophily
- Ornithophily
- Cheiropteriphily
- Malacophily
- Outbreeding Devices
- Fertilization
- Pollen Pistil Interaction
- Artificial Hybridization or Artificial Fertilization
- Double Fertilization and Triple Fusion
- Endosperm
- Embryo
- Seed and Fruit Development
- Dormancy
- Apomixis
- Parthenocarpy
- Polyembryony
- Overview of Reproduction in Lower and Higher Plants
Reproduction in Lower and Higher Animals
- Reproduction
- Asexual Reproduction
- Asexual Reproduction in Multicellular Organisms > Gemmule Formation
- Asexual Reproduction in Multicellular Organisms > Budding
- Asexual Reproduction in Multicellular Organisms > Regeneration
- Sexual Reproduction
- Human Reproduction
- The Male Reproductive System
- Basic Concept of Testes
- Duct system of Male Reproductive Tract
- Accessory Glands of Male Reproductive System
- Semen (Seminal fluid)
- External Genitalia: Penis
- The Female Reproductive System
- Ovaries
- Female Reproductive Duct System
- External Genitalia: Vulva
- Mammary Glands
- Puberty
- Menstrual Cycle (Ovarian Cycle)
- Major Events of Menstrual Cycle
- Gametogenesis
- Spermatogenesis
- Phases of Spermatogenesis
- Structure of Sperms
- Oogenesis
- Phases of Oogenesis
- Structure of Secondary Oocyte
- Fertilization
- Fertilization in Human
- Embryonic Development in Human
- Pregnancy in Humans
- Placenta (Growth) in Human
- Parturition (Birth) in Human
- Lactation in Human
- Concept of Reproductive Health
- Methods of Birth Control and Contraceptive Devices
- Natural Contraceptive Methods
- Artificial Contraceptive Methods
- Sexually Transmitted Diseases (STD) or Sexually Transmitted Infections (STI)
- Infertility
- Assisted Reproductive Technology (ART)
- Overview of Reproduction in Lower and Higher Animals
Inheritance and Variation
- Heredity
- Genes and Genetic
- Back Cross and Test Cross
- Deviations from Mendel’s Findings
- Chromosomal Theory of Inheritance
- Chromosomes - The Carriers of Heredity
- Linkage and Crossing Over
- Autosomal Inheritance
- Sex Determination
- Sex Linked Inheritance
- Human Genetic Disorders
- Exceptions to Mendel's Principles > Multiple alleles
- Linkage
- Types of Linkage > Complete Linkage
- Types of Linkage > Incomplete Linkage
- Crossing Over
- Colour blindness
- Haemophilia
- Sex Determination in Birds
- Down's syndrome (Mongolian Idiocy)
- Turner's Syndrome
- Klinefelter's Syndrome
- Overview of Inheritance and Variation
Molecular Basis of Inheritance
- Deoxyribonucleic Acid (DNA)
- Griffith’s Experiment
- Packaging of DNA Helix
- DNA Replication
- Protein Synthesis
- Regulation of Gene Expression
- The Lac Operon
- Genomics
- Human Genome Project
- DNA Fingerprinting
- Genetic Code
- Mechanism of Translation
- Overview of Molecular Basis of Inheritance
Origin and Evolution of Life
- Origin and Evolution of Universe and Earth
- Theories of Origin of Life
- Chemical Evolution of Life (Self-assembly Theory of the Origin of Life)
- Darwin’s Theory of Natural Selection (Darwinism)
- Mutation Theory
- Modern Synthetic Theory of Evolution
- Organic Evolution
- Hardy Weinberg’s Principle
- Adaptive Radiation
- Evidence of Evolution > Morphological Evidences
- Speciation
- Geological Time Scale
- Theories of Biological Evolution
- Overview of Origin and Evolution of Life
Plant Water Relation
- Plant Water Relation
- Properties of Water
- Water Available to Roots for Absorption
- Imbibition
- Diffusion
- Osmosis
- Osmotic Pressure
- Turgidity and Flaccidity (Plasmolysis)
- Passive Transport
- Water Potential (ψ)
- Concept of Transpiration
- Path of Water Across the Root
- Kinds of Transpiration
- Forces Contributing to Ascent of Sap
- Transport of Mineral Ions
- Structure of Stomatal Apparatus
- Significance of Transpiration
- Transportation of Food and Other Substances
- Overview of Plant Water Relation
Plant Growth and Mineral Nutrition
- Plant Growth
- Phases of Plant Growth
- Conditions Necessary for Plant Growth
- Plant Growth Rate
- Plant Growth Curve
- Differentiation, De-differentiation, Re- Differentiation
- Plant Development
- Plant Plasticity
- Plant Hormones
- Auxins
- Gibberellins
- Cytokinins
- Ethylene
- Abscisic Acid (ABA)
- Photoperiodism
- Vernalization (Yarovization)
- Plant Mineral Nutrition
- Nitrogen Cycle
- Overview of Plant Growth and Mineral Nutrition
Respiration and Circulation
- Cellular Respiration
- Organs of Respiratory Exchange
- Human Respiratory System
- Mechanism of respiration-Breathing
- Regulation of Breathing / Respiration
- Modified Respiratory Movements
- Disorders of Respiratory System
- Transportation in Living Organisms
- Circulation in Animals
- Types of Closed Circulation
- Blood Circulatory System
- Composition of Blood > Plasma (The Liquid Portion of Blood)
- Composition of Blood > Cellular Elements: Red Blood Cells (Erythrocytes)
- Composition of Blood > Cellular Elements: White Blood Cells (Leukocytes)
- Composition of Blood > Cellular Elements: Blood Platelets (Thrombocytes)
- Human Heart
- Working mechanism of human heart
- Blood Vessels
- Blood Pressure (B.P.)
- Electrocardiogram (ECG)
- Lymph and Lymphatic System
- Mechanism of respiration - Internal respiration
- Mechanism of respiration - External respiration
- Cellular Respiration
- Overview of Respiration and Circulation
Control and Co-ordination
- Control and Co-ordination
- Nervous System in Hydra
- Nervous System in Planaria (Flatworm)
- Neural Tissue
- Neuron (Or Nerve Cell)
- Neuroglial Cells (Or Glial Cells)
- Human Nervous System
- Central Nervous System (CNS)
- The Human Brain
- The Spinal Cord
- Peripheral Nervous System > Somatic Nervous System
- Sensory Receptors
- The Human Eye
- Human Ear
- Disorders of Nervous System
- Chemical Coordination
- Human Endocrine System
- The Hypothalamus
- Pituitary Gland or Hypophysis Gland
- The Pineal Gland
- Thyroid Gland
- Parathyroid Gland
- Thymus Gland
- Adrenal Gland (Suprarenal Gland)
- Pancreas (Islets of Langerhans)
- Reproductive Glands (Gonads)
- Synapse
- Types of Synapse
- Transmission of Nerve Impulse
- Generation of nerve impulse
- Reflex Action
- Peripheral Nervous System > Autonomic Nervous System
- Diffuse Endocrine Glands
- Overview of Control and Co-ordination
Human Health and Diseases
- Defence System in Our Body: Immune System
- Structure of Antibody
- Disease
- Protozoan Diseases
- Helminthic Diseases
- Bacterial Diseases
- Viral Diseases
- Fungal Diseases
- Vector Borne Diseases
- Cancer
- Drug Abuse
- Concept of Adolescence
- Addiction
- Vaccines and Vaccination
- Blood Transfusion and Blood Groups (ABO and Rh system)
Human Reproduction
Enhancement of Food Production
- Improvement in Food Production
- Plant Breeding
- Tissue Culture
- Single Cell Protein (SCP)
- Biofortification
- Animal Husbandry (Livestock)
- Animal Husbandry (Livestock) > Animal Breeding
- Dairy (Livestock) Farm Management
- Poultry Farm Management
- Animal Husbandry (Livestock) > Apiculture (Bee Farming)
- Animal Husbandry (Livestock) > Pisciculture (Fish Farming)
- Sericulture
- Lac Culture
- Microbes in Human Welfare
- Microbes in Industrial Products
- Microbes in Sewage Treatment
- Microbes in Energy Generation
- Microbes as Biocontrol Agents
- Microbes as Biofertilizers
- Microbial Role in Dairy Products
- Overview of Enhancement of Food Production
Biotechnology
- Biotechnology
- Principles of Biotechnology
- Methodology for rDNA Technology
- Crop Biotechnology > Hybrid Seeds
- Bioethics
- Effects of Biotechnology on the Environment
- Biopiracy
- Transgenic Plants
- Effects of Biotechnology on Human Health
- Tools and techniques for gene cloning/ rDNA technology
- Crop Biotechnology > Genetically Modified Organisms (GMOs)
- Overview of Biotechnology
Organisms and Populations
- Organisms and the Environment Around
- Habitat
- Niche
- Adaptations and Its Types
- Population
- Population Interactions
- Organisms and Populations
- Population Growth
- Positive Interactions > Mutualism (Symbiosis)
- Negative Interactions > Competition
- Negative Interactions > Parasitism
- Negative Interactions > Predation
- Positive Interactions > Commensalism
- Overview of Organisms and Populations
Ecosystems and Energy Flow
Biodiversity, Conservation and Environmental Issues
- Biodiversity
- Levels of Biodiversity
- Patterns of Biodiversity
- Biodiversity Current Scenario
- Loss of Biodiversity
- Conservation of Wildlife
- Biological Diversity Act, 2002
- Environmental Issues
- Noise Pollution
- Green House Effect
- Preventive Measures of Green House Effect
- Deforestation and Its Causes
- Global Warming
- Preventive Measures of Global Warming
- Mission Harit Maharashtra
- Conservation of Biodiversity
- Overview of Biodiversity, Conservation and Environmental Issues
- Structure of the Heart
- Layers of the Heart Wall
- Chambers of the Heart
- Definition: Pericardium
- Key Points: The Heart
Maharashtra State Board: Class 8
Structure of the Heart
The heart is located almost at the centre of the thoracic cage. It is situated behind the ribs, between the two lungs, and slightly inclined to the left side.
- The size of our heart is approximately equal to one's own fist, and it weighs about 360 grams. It is covered by a double-layered peritoneal membrane.
- A fluid is present between the two membranes, which protects the heart from friction and mechanical shocks.
- The human heart is a muscular organ composed of involuntary cardiac muscles. These muscles contract and relax with a definite rhythm, known as the beating of the heart.
The human heart is a four-chambered muscular organ, about the size and shape of a closed fist. Two-thirds of the heart's mass is positioned to the left of the midline of the body. The heart is enclosed in a pericardial sac, providing protection and support. The sac is lined with the parietal layer of a serous membrane. The visceral layer of this serous membrane forms the epicardium, which is the outer layer of the heart.
Structure of Heart and Blood Circulation
Maharashtra State Board: Class 8
Layers of the Heart Wall
- Epicardium (Outer Layer): The epicardium is the outermost layer of the heart wall. It serves as a protective layer and is made up of connective tissue. It also contains blood vessels and nerves that supply the heart.
- Myocardium (Middle Layer): The myocardium is the thickest and most muscular layer of the heart wall. It is composed of cardiac muscle tissue that contracts to pump blood. This layer is responsible for the heart's powerful beating action.
- Endocardium (Inner Layer): The endocardium is the innermost layer of the heart wall. It is a thin, smooth layer that lines the inside of the heart chambers. It helps to prevent blood from sticking to the heart walls and keeps the heart functioning smoothly.
Maharashtra State Board: Class 8
Chambers of the Heart
The internal cavity of the heart is divided into four chambers:
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
The atria are the upper, thin-walled chambers of the heart. They receive blood from veins: the right atrium gets deoxygenated blood from the body, and the left atrium gets oxygenated blood from the lungs.
The ventricles are the lower, thick-walled chambers of the heart. They pump blood forcefully: the right ventricle sends deoxygenated blood to the lungs, and the left ventricle pumps oxygenated blood to the entire body.
The thickness of the chamber walls varies because thicker walls (more myocardium) are needed to generate more force for pumping blood.
CISCE: Class 10
Definition: Pericardium
CISCE: Class 10
Key Points: The Heart
- The heart is located centrally between the lungs, but its pointed lower end tilts to the left, making it feel like it's on the left side.
- It is enclosed in a double-walled membrane called the pericardium, which contains pericardial fluid to reduce friction and protect the heart.
- The heart has four chambers—two upper atria and two lower ventricles; atria have thinner walls as they only pump blood into ventricles.
- Ventricles have thicker muscular walls to pump blood further; the left ventricle is the thickest as it pumps blood to the entire body.
- The right ventricle sends deoxygenated blood to the lungs for oxygenation, while the left ventricle sends oxygenated blood to all body parts.
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