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Cells as Basic Units of Life

• Cells are the fundamental structural and functional units of all living organisms
• Two categories of cells: eukaryotic and prokaryotic

Eukaryotic Cells

• Defined nucleus enclosed by a membrane
• Examples include plant and animal cells
• Organelles include nucleus, mitochondria, and vacuoles

Prokaryotic Cells

• Lack a nucleus; genetic material is not enclosed within a membrane
• Examples include bacteria

Common Cell Structures

• Cell membrane, cytoplasm and nucleus

Cell Membrane

• A selectively permeable barrier that surrounds the cell
• Regulates the movement of substances in and out of the cell
• Composed primarily of lipids and proteins

Cytoplasm

• The jellylike substance within the cell membrane, excluding the nucleus
• Contains cytosol, the aqueous part with water, salts, and organic molecules
• Contains organelles (mitochondria and vacuoles) that perform specific functions

Nucleus (in Eukaryotic Cells)

• The control center of the cell, containing DNA
• Regulates cellular activities
• Has a double membrane with pores for material exchange
• Contains a nucleolus where ribosomal RNA is synthesized

Specialised Cells

• Cells vary in shape, size, and function, leading to specialisation

Nerve Cells

• Specialized for transmitting electrical signals
• Often long and branched

Red Blood Cells

• Specialized for carrying oxygen
• Have a biconcave shape to increase surface area

Organelles and Their Functions

• Mitochondria and Vacuoles

Mitochondria

• The powerhouse of the cell, where cellular respiration occurs
• Converts food into usable energy
• Enclosed by a double membrane
• Inner membrane folds to form cristae

Vacuoles

• Storage of nutrients, waste products, and other substances
• Helps maintain turgor pressure in plant cells
• Membrane-bound sacs within the cytoplasm

Key Terms and Concepts

• Cytoplasm, microscope, microscopic, organelle, cellular respiration, DNA, selective permeability

Cytoplasm

• The entire contents within the cell membrane, excluding the nucleus in eukaryotic cells

Microscope

• An instrument used to view microscopic cells and their structures

Microscopic

• Describes objects that are too small to be seen without a microscope

Organelle

• Specialized structures within a cell that perform specific functions

Cellular Respiration

• The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water

DNA (Deoxyribonucleic Acid)

• The molecule that contains genetic information
• Determines inherited traits and directing cellular functions

Selective Permeability

• The property of the cell membrane that allows some substances to pass through while blocking others

Variations in DNA and Heredity

• Hereditary traits and variation

Hereditary Traits

• Characteristics passed from parents to offspring through DNA

Variation

• Differences in DNA sequences that lead to diversity within and between species

Study of Cells

• Cytology and protoplasm

Cytology

• The scientific study of cells, encompassing their structure, function, and significance

Protoplasm

• The living content of a cell, comprising the cytoplasm and nucleus

Differences Between Plant and Animal Cells

• Plant and animal cells exhibit significant differences due to their distinct roles and functions

Cell Wall

• Plant cells have an additional outer layer called the cell wall
• Provides structural support, protection, and rigidity
• Composed of cellulose

Functions and Structure of the Cell Wall

• Protection, support, and regulation

Protection

• It protects plant cells from mechanical damage and pathogenic attack

Support

• It provides structural integrity, enabling plants to maintain their shape and stand upright

Regulation

• It regulates the entry and exit of substances

Cell Walls in Other Organisms

• Bacterial cell walls contain peptidoglycan
• Fungal cell walls contain chitin

Chloroplasts

• Specialized organelles found in plant cells and certain algae
• Absent in animal cells
• Responsible for photosynthesis

Structure and Function of Chloroplasts

• Thylakoids, stroma, and chlorophyll

Thylakoids

• Membranebound structures where light-dependent reactions occur

Stroma

• Fluid-filled space where the Calvin cycle takes place

Chlorophyll

• Green pigment that captures light energy

Vacuoles

• Large, membrane-bound sacs within plant cells
• Store nutrients and waste products
• Help maintain turgor pressure

Functions of Vacuoles

• Storage, support, detoxification, and growth

Storage

• They store nutrients, waste products, and other substances

Support

• Vacuoles help maintain turgor pressure

Detoxification

• They can sequester harmful substances

Growth

• Enable cell growth by absorbing water and expanding

Turgor Pressure

• Full vacuoles mean cells are turgid
• Loss of water causes cells to become flaccid

Vacuoles in Animal Cells

• Animal cells may have small, temporary vacuoles

Additional Differences

• Shape and structure, centrioles, plasmodesmata, lysosomes, peroxisomes, and energy storage

Shape and Structure

• Plant cells typically have a fixed, rectangular shape
• Animal cells often have an irregular, flexible shape

Centrioles

• Plant cells generally lack centrioles
• Animal cells contain centrioles for cell division

Plasmodesmata

• Plant cells contain plasmodesmata for intercellular communication
• Animal cells have gap junctions for a similar function

Lysosomes

• Plant cells rarely have lysosomes
• Animal cells contain lysosomes for breaking down cellular waste

Peroxisomes

• Both cell types contain peroxisomes for breaking down fatty acids
• They also detoxify harmful substances.
• Plant cells' peroxisomes involved in the glyoxylate cycle

Energy Storage

• Plant cells store energy primarily in the form of starch
• Animal cells store energy in the form of glycogen

Cells in Tissues, Organs, and Systems

• To understand the structure and function of cells, it is essential to observe them under a microscope

Observing Cells Under a Microscope

• Microscopes magnify objects too small to be seen with the naked eye
• Modern electron microscopes use electrons to see fine details

Types of Microscopes

• Light and electron microscopes

Light Microscopes

• Use visible light to illuminate specimens and lenses to magnify images
• Suitable for viewing live cells and tissues

Electron Microscopes

• Use beams of electrons for higher magnification and resolution
• Suitable for viewing the ultrastructure of cells and tissues

Parts of a Light Microscope

• Eyepiece, objective lenses, stage, light source, focus knobs, and diaphragm

Eyepiece (Ocular Lens)

• The lens you look through, typically magnifies 10x

Objective Lenses

• Multiple lenses with different magnifications
• E.g., 4x, 10x, 40x, 100x

Stage

• The platform where the slide is placed

Light Source

• Illuminates the specimen

Coarse and Fine Focus Knobs

• Adjust the focus of the image

Diaphragm

• Controls the amount of light reaching the specimen

Microscope Safety Precautions

• Carry with two hands, place on a stable surface, clean lenses with lens paper, use unbroken slides, focus slowly, and store properly

Preparing Specimens For Microscopic Observation

• Wet mount, dry mount, smear and staining

Wet Mount

• Used for observing living organisms and aquatic samples
• A drop of liquid (water, brine, glycerine, or immersion oil) is placed on the slide.
• The specimen is placed in the liquid, and a cover slip is gently lowered to avoid air bubbles

Dry Mount

• Used for observing hair, feathers, pollen grains, or dust
• The specimen is placed directly on the slide without liquid

Smear

• Often used for blood or other bodily fluids
• The sample is spread thinly across the slide and allowed to dry

Staining

• Enhances contrast and allows for better visualization of structures
• Common stains include iodine solution, methylene blue, and crystal violet

Differentiation of Cells in Tissues, Organs, and Systems

• Cells vary greatly in shape and size depending on their specific functions
• This diversity is crucial for the functioning of multicellular organisms

Specialization and Differentiation

• Differentiated cells have unique structures that enable them to fulfill their roles effectively

Examples of Specialized Cells

• Epithelial, muscle, nerve, and red blood cells

Epithelial Cells

• Mostly flat cells that cover surfaces and protect the body

Muscle Cells

• Long and spindle shaped cells that contract and relax to enable movement

Nerve Cells

• Long cells with branched ends specialized for transmitting electrical signals

Red Blood Cells

• Round and biconcave cells that carry oxygen and carbon dioxide

Stem Cells

• Unspecialized cells capable of dividing and differentiating into various specialized cells
• Crucial for growth, development, and tissue repair

Types of Stem Cells

• Embryonic and adult stem cells

Embryonic Stem Cells

• Can become any cell type in the body

Adult Stem Cells

• Found in tissues like bone marrow
• Limited in their differentiation potential but essential for tissue maintenance and repair

Microscopic vs Macroscopic Organisms

• Unicellular and multicellular

Unicellular Organisms

• Consist of a single cell that performs all life functions
• Examples include bacteria, amoebae, and certain algae
• Can only be seen with a microscope

Multicellular Organisms

• Composed of many cells that specialize and work together
• Examples include plants, animals, and fungi
• Visible to the naked eye

Organization of Cells in Multicellular Organisms

• Cells are organized into tissues, organs, and systems to perform complex functions

Hierarchy of Organization

• Cells -> Tissues -> Organs -> Organ Systems -> Organism

Example: The Digestive System

• Cells: Epithelial cells, muscle cells.
• Tissues: Epithelial tissue, muscle tissue.
• Organs: Mouth, esophagus, stomach, intestines, liver, pancreas.
• System: Digestive system.

Practical Activity: Observing Cells

• Prepare the microscope, prepare the slide, observe the specimen, and draw and label observations

Prepare the Microscope

• Ensure the microscope is clean and properly set up
• Use the lowest magnification to locate the specimen

Prepare the Slide

• For a wet mount, place a drop of liquid on the slide
• Add the specimen to the liquid
• Gently place the cover slip to avoid air bubbles

Observe the Specimen

• Adjust the light source for optimal illumination
• Use the coarse focus knob to bring the specimen into general focus
• Use the fine focus knob to sharpen the image

Draw and Label Observations

• Make detailed drawings of the observed cells
• Label the different structures and organelles

The Digestive System

• The purpose of the digestive system is to break down food into small particles that can be absorbed into the bloodstream

Components of the Digestive System

• Mouth and Oesophagus, stomach, small intestine, large intestine, rectum, anus

Mouth and Oesophagus

• Digestion begins in the mouth where food is chewed and mixed with saliva
• Saliva contains enzymes that start breaking down carbohydrates
• The oesophagus is a muscular tube that moves food from the mouth to the stomach through peristaltic contractions

Stomach

• The stomach further digests food using gastric juices and enzymes
• The stomach's muscular walls contract to turn the food into a semiliquid substance called chyme

Small Intestine

• The majority of digestion and nutrient absorption occurs in the small intestine
• Enzymes from the pancreas and bile from the liver aid in breaking down food into nutrients that can be absorbed

Large Intestine (Colon)

• The large intestine absorbs water and salts from the remaining food matter and compacts it into feces
• Beneficial bacteria in the colon also produce certain vitamins like Vitamin K and some B vitamins

Rectum and Anus

• The rectum stores feces until they are expelled through the anus during the process of egestion

Main Processes in the Digestive System

• Ingestion, digestion, absorption, egestion

Ingestion

• Taking food into the body through the mouth by eating or drinking

Digestion

• Breaking down food into smaller particles that can be absorbed
• Involves mechanical digestion (chewing and stomach contractions) and chemical digestion (enzymes breaking down food)

Absorption

• Nutrients from digested food are absorbed into the cells of the digestive tract and then into the bloodstream

Egestion

• Removal of undigested or unwanted particles from the body as feces

Health Issues Involving the Digestive System

• Ulcers, anorexia nervosa, diarrhea, and liver cirrhosis

Ulcers

• Open sores that develop on the lining of the mouth, oesophagus, stomach, or upper small intestine
• Often caused by bacterial infections or certain medications

Anorexia Nervosa

• An eating disorder involving an intense fear of gaining weight
• Leads to severe food restriction and starvation

Diarrhea

• Frequent, loose, watery stools
• Caused by diseases or conditions that cause food to pass too quickly through the large intestine

Liver Cirrhosis

• A disease that gradually replaces healthy liver tissue with scar tissue
• Common causes include alcohol abuse and obesity

The Circulatory System

The purpose of the circulatory system is to transport blood throughout the body

• It delivers oxygen and nutrients to cells and removes carbon dioxide and waste products
• The system also plays a crucial role in regulating body temperature and maintaining homeostasis

Components of the Circulatory System

• Heart, blood vessels, blood.

Heart

• The heart is a muscular organ that pumps blood through the body
• It consists of four chambers: two atria (upper chambers) and two ventricles (lower chambers)

Blood Vessels

• Arteries, Capillaries and Veins

Arteries

• Carry oxygenated blood away from the heart to the tissues of the body
• The largest artery is the aorta

Capillaries

• Tiny blood vessels where the exchange of gasses, nutrients, and waste products occurs between blood and tissues

Veins

• Carry deoxygenated blood back to the heart. The largest vein is the vena cava.

Blood

• Composed of plasma (the liquid component), red blood cells (which carry oxygen), white blood cells (which fight infection), and platelets (which help with clotting)

Main Processes in the Circulatory System

• Pulmonary circulation and systemic circulation

Pulmonary Circulation

• Blood circulates between the heart and the lungs
• Deoxygenated blood is pumped from the right ventricle to the lungs via the pulmonary arteries
• In the lungs, carbon dioxide is exchanged for oxygen. Oxygenated blood returns to the left atrium via the pulmonary veins

Systemic Circulation

• Oxygenated blood is pumped from the left ventricle through the aorta to the rest of the body
• Arteries and capillaries distribute oxygen and nutrients to cells
• Deoxygenated blood returns to the right atrium via the veins

Health Issues Involving the Circulatory System

• High blood pressure, heart attacks, strokes

High Blood Pressure

• Occurs when the force of blood against the artery walls is too high
• Can damage blood vessels and organs
• Can lead to heart disease, stroke, kidney failure, and other serious health problems.

Heart Attacks

• Occurs when a blood clot blocks one of the coronary arteries, which supply blood to the heart muscle
• Can stop the flow of oxygen rich blood to part of the heart.
• The affected heart muscle can be damaged or die

Strokes

• Occurs when the blood supply to part of the brain is interrupted or reduced
• Caused by a blockage in a blood vessel (ischemic stroke) or a blood vessel rupturing (hemorrhagic stroke).
• Brain cells begin to die within minutes

The Respiratory System

• The respiratory system is responsible for the vital exchange of gasses between the body and the environment

Components of the Respiratory System

• Mouth and nose, pharynx, trachea, bronchi, lungs, alveoli, diaphragm

Mouth and Nose

• Air enters the body through the mouth and nose
• Air is warmed, moistened, and filtered in the nasal cavity

Pharynx

• Serves as a passageway for both air and food
• Connects the nasal cavity and mouth to the larynx and oesophagus

Trachea

• Supported by C Shaped rings of cartilage
• Conducts air from the pharynx to the bronchi
• Inner lining is covered with mucus and cilia to trap and expel foreign particles

Bronchi

• The trachea divides into two bronchi, each leading to a lung
• These further divide into smaller bronchioles, resembling an inverted tree structure, distributing air throughout the lungs

Lungs

• The main organs of the respiratory system, located in the thoracic cavity
• Contain millions of tiny air sacs called alveoli

Alveoli

• Small, balloon-like structures at the end of bronchioles
• Thin walls facilitate the diffusion of oxygen into the blood and carbon dioxide out of the blood

Diaphragm

• A dome shaped muscle located beneath the lungs
• Plays a crucial role in breathing by contracting and relaxing

Main Processes in the Respiratory System

• Breathing, gaseous exchange, cellular respiration

Breathing

• Inhalation and exhalation

Inhalation

• The diaphragm contracts and moves downward
• The intercostal muscles contract, expanding the rib cage
• This increases the volume of the thoracic cavity, reducing pressure inside the lungs and causing air to flow in

Exhalation

• The diaphragm relaxes and moves upward, and the intercostal muscles relax, causing the rib cage to contract
• This decreases the volume of the thoracic cavity, increasing pressure inside the lungs and pushing air out

Gaseous Exchange

• In the alveoli: Oxygen from the inhaled air diffuses through the alveolar walls into the capillaries
• Carbon dioxide from the blood diffuses into the alveoli to be exhaled
• At the body tissues: Oxygen diffuses from the blood into the cells
• Carbon dioxide diffuses from the cells into the blood

Cellular Respiration

• Cellular respiration occurs within the mitochondria of cells, where oxygen is used to convert glucose and other nutrients into ATP
• This process produces carbon dioxide and water as byproducts

Health Issues Involving the Respiratory System

• Asthma, lung cancer, bronchitis, pneumonia, tuberculosis

Asthma

• A chronic condition characterized by inflammation and narrowing of the airways

Lung Cancer

• A malignant disease often caused by smoking

Bronchitis

• Inflammation of the lining of the bronchial tubes, often caused by viral or bacterial infections

Pneumonia

• An infection that inflames the air sacs in one or both lungs, which may fill with fluid or pus

Tuberculosis (TB)

• An infectious disease caused by the bacterium Mycobacterium tuberculosis

The Musculoskeletal System

• Enables body movement and supports its structure
• Muscles, tendons, ligaments, bones, and joints work together

Components of the Musculoskeletal System

• Muscles, bones, cartilage, tendons, ligaments

Muscles

• Responsible for movement through contraction and relaxation

Bones

• Provide structural support and shape and protect vital organs

Cartilage

• Found between bones, in the ears, nose, and between spinal discs, it is stiff yet flexible.

Tendons

• Connect muscles to bones

Ligaments

• Connect bones at joints and provide stability

Main Processes in the Musculoskeletal System

• Locomotion and movement

Locomotion

• The ability to move the entire body from one place to another

Movement

• Change in shape, direction, position, or size of a body part

Health Issues Involving the Musculoskeletal System

• Rickets, arthritis, osteoporosis

Rickets

• Caused by deficiencies in vitamin D, calcium, or phosphate

Arthritis

• Inflammation and pain in joints due to the breakdown of cartilage

Osteoporosis

• Characterized by brittle and fragile bones that break easily

The Excretory System

• The excretory system is responsible for removing metabolic waste products
• Helps maintain homeostasis

Components of the Excretory System

• Kidneys, ureters, bladder, urethra

Kidneys

• Filter blood to remove waste products and excess substances
• Produce urine
• Play a crucial role in maintaining fluid and electrolyte balance

Ureters

• Thin tubes that transport urine from each kidney to the bladder

Bladder

• A hollow, balloon like organ that stores urine

Urethra

• A tube that connects the bladder to the exterior of the body, allowing urine to be excreted

Main Processes in the Excretory System

• Filtration, reabsorption, secretion, excretion

Filtration

• Water, salts, glucose, amino acids, and waste products are filtered out of the blood
• Larger molecules like proteins and blood cells remain in the bloodstream

Reabsorption

• Essential substances such as glucose, amino acids, and a portion of water and salts are reabsorbed back into the bloodstream

Secretion

• Additional waste products and excess ions are secreted from the blood into the renal tubules

Excretion

• The final urine, including waste products and excess substances, is funneled from the nephrons into collecting ducts

Health Issues Involving the Excretory System

• Kidney failure, kidney stones, bladder infections, glomerulonephritis, polycystic kidney disease

Kidney Failure

• Occurs when the kidneys lose their ability to filter blood effectively

Kidney Stones

• Hard deposits of minerals and salts that form in the kidneys when urine becomes concentrated

Bladder Infections

• Occur when bacteria enter the bladder and cause inflammation

Glomerulonephritis

• Inflammation of the glomeruli in the kidneys

Polycystic Kidney Disease

• A genetic disorder characterized by the growth of numerous cysts in the kidneys

The Nervous System

• Transmits nerve impulses, coordinates the body's actions and sensory information

Components of the Nervous System

• Nerves, brain, spinal cord, sensory organs

Nerves

• Bundles of nerve cells that transmit messages to and from the brain and spinal cord to the rest of the body

Brain

• Controls various functions, including thought, memory, emotion, touch, motor skills, vision, breathing, temperature regulation

Spinal Cord

• Transmits signals between the brain and the rest of the body
• Protected by the vertebral column

Sensory Organs

• Collect information from the environment and send it to the central nervous system for processing

Main Processes in the Nervous System

• Sending and receiving impulses, hearing, seeing, feeling, tasting, smelling, regulating body temperature

Sending and Receiving Impulses

• Neurons send and receive messages through electrical impulses

Hearing

• Sound waves are transformed into electrical signals by hair cells in the cochlea
• These signals travel along the auditory nerve to the brain, where they are interpretted

Seeing

• Light enters the eye and stimulates photoreceptor cells in the retina

Feeling

• Sensory receptors in the skin detect pressure, temperature, and pain

Tasting

• Taste buds on the tongue detect different flavours

Smelling

• Olfactory receptors in the nasal cavity detect airborne chemicals

Regulating Body Temperature

• The hypothalamus in the brain helps regulate body temperature

Health Issues Involving the Nervous System

• Trauma and injuries to brain and spinal cord, stroke, degenerative disorders, mental health problems, sensory organ problems, effects of drugs and alcohol on the brain

Trauma and Injuries to Brain and Spinal Cord

• Damage to the brain or spinal cord can result in severe and often irreversible consequences, including paralysis

Stroke

• Occurs when blood flow to the brain is interrupted

Degenerative Disorders

• Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis

Mental Health Problems

• Conditions such as depression, anxiety, and personality disorders

Sensory Organ Problems

• Deafness, blindness, and shortsightedness

Effects of Drugs and Alcohol on the Brain

• Substance abuse can cause cognitive impairment and brain damage

The Reproductive System

• The primary purpose of the reproductive system is to produce sex cells and ensure the continuation of the species through sexual reproduction

Components of the Reproductive System

• Female and male reproductive system

Female Reproductive System

• Ovaries, uterus, fallopian tubes, vagina

Ovaries

• Produce ova (egg cells) and release them during ovulation

Uterus

• Where a fertilized egg implants and develops into a fetus during pregnancy

Fallopian Tubes

• Connect the ovaries to the uterus; fertilization typically occurs here

Vagina

• A muscular canal that connects the cervix to the outside of the body

Male Reproductive System

• Testes, scrotum, penis, epididymis, vas deferens, urethra

Testes

• Produce sperm cells and the male sex hormone testosterone

Scrotum

• Houses the testes and regulates their temperature

Penis

• The external organ used for urination and sexual intercourse

Epididymis

• Where sperm mature and are stored before ejaculation

Vas Deferens

• Ducts that transport mature sperm from the epididymis to the urethra

Urethra

• Carries urine in males and also semen

Main Processes in the Reproductive System

• Ovulation, fertilization, implantation, menstruation, ejaculation

Ovulation

• An ovary releases a mature egg

Fertilization

• A sperm cell combines with an egg cell

Implantation

• The zygote implants itself into the lining of the uterus

Menstruation

• The lining of the uterus is shed through the vagina

Ejaculation

• The release of semen, which contains sperm, from the penis

Health Issues Involving the Reproductive System

• Infertility, Foetal Alcohol Syndrome (FAS), Sexually Transmitted Diseases (STDs), Endometriosis, Prostate Issues

Infertility

• Makes it difficult to conceive a child

Foetal Alcohol Syndrome

• Occurs when a pregnant woman consumes alcohol

Sexually Transmitted Diseases

• Infections that are passed from one person to another through sexual contact

Endometriosis

• Tissue similar to the lining inside the uterus grows outside the uterus

Prostate Issues

• Common in older men and can cause urinary problems

The Purpose of Reproduction

• Reproduction is a fundamental life process essential for the survival of species
• Human reproduction involves the production of sex cells (gametes) by males and females
• This process ensures the continuation of the species and the passing on of genetic material

The Purpose of Puberty

• Puberty is the developmental stage during which bodies mature into adult bodies capable of sexual reproduction

How Puberty Just "Start"

• Puberty begins when the pituitary gland releases hormones into the bloodstream
• These hormones signal the immature sex organs to start producing their own hormones

Changes During Puberty

• Results in both primary and secondary sexual characteristics

Changes in Females

• Breast development
• Growth of pubic and underarm hair
• Menstruation
• Body shape changes
• Body odour and acne

Changes in Males

• Increase in testicle and penis size
• Growth of body hair
• Voice deepening
• Body shape changes
• Body odour and acne

Hormones and Puberty

• Hormones are chemical messengers produced by glands in the endocrine system

Estrogen

• Produced by the ovaries in females
• Responsible for the development of female secondary sexual characteristics and the regulation of the menstrual cycle

Testosterone

• Produced by the testes in males
• Responsible for the development of male secondary sexual characteristics and the production of sperm

Male Reproductive Organs

• Designed to produce, maintain, and transport sperm

Testes and Scrotum

• Oval shaped organs that produce sperm and testosterone
• The scrotum regulates the temperature of the testes

Sperm Duct (Vas Deferens)

• A muscular tube that transports mature sperm from the epididymis to the urethra

Penis

• The external male sex organ which is composed of spongy tissue that fills with blood when erect

Urethra

• A tube that runs through the penis which carries both urine and semen

Female Reproductive Organs

• Designed to produce ova, facilitate fertilization, and support the development of a foetus

Vagina

• A muscular canal that connects the cervix of the uterus to the external genitalia

Uterus

• Responsible for housing and nourishing a fertilized egg

Ovaries

• Small, almond shaped organs that produce female sex hormones and store and release eggs

Oviducts (Fallopian Tubes)

• Narrow tubes that connect the ovaries to the uterus

Stages of Reproduction

• The reproductive cycle, fertilisation, pregnancy and birth

The Reproductive Cycle

• A recurring process that prepares the body for potential pregnancy

Ovulation

• The release of a mature egg from one of the ovaries

Menstruation

• If the egg is not fertilized, the thickened uterine lining is shed and expelled from the body through the vagina

Fertilization

• The male penis deposits sperm into the female vagina through ejaculation

Journey of Sperm

• Sperm swim through the cervix, into the uterus, and towards the oviducts

Penetration of the Egg

• One sperm penetrates the outer membrane of the egg

Pregnancy and Birth

• Begins when a sperm fertilizes an egg, forming a zygote

Formation and Implantation of the Embryo

• The zygote begins to divide and grow as it travels down the oviduct

Placenta and Umbilical Cord Development

• The embryo forms the placenta and umbilical cord

Gestation

• Human pregnancy lasts about 40 weeks (9 months)

Labour and Birth

• The uterus begins to contract, and these contractions push the foetus's head into the vagina

Health Issues Related to Reproduction

• Infertility, foetal alcohol syndrome, sexually transmitted diseases

Infertility

• Affects about 10% of heterosexual couples and is the inability to conceive after a year of regular, unprotected intercourse

Foetal Alcohol Syndrome

• Consumption of alcohol during pregnancy can cause serious birth defects

Sexually Transmitted Diseases

• Can be transmitted during sexual intercourse

Human Reproduction System

• Breathing, or respiration, is a vital process that involves two main stages: inhalation and exhalation

Inhalation

• The rib cage moves upwards and outwards
• The diaphragm contracts and flattens, moving downwards
• This increases the volume of the chest cavity, reducing the pressure inside
• The lungs expand to fill the extra space, allowing air to be pulled into them

Exhalation

• The rib cage moves downwards and inwards
• The diaphragm relaxes, becoming dome shaped again
• This decreases the volume of the chest cavity, increasing the pressure inside
• The lungs are compressed, forcing air out of them

Air Pathway

• Mouth and nose -> pharynx and larynx -> trachea -> two bronchi , each leading to one lung - > Thousands of tiny bronchioles

Gas Exchange

• Oxygen from inhaled air diffuses through the thin walls of the alveoli and into the blood in the capillaries
• Carbon dioxide from the blood diffuses into the alveoli to be exhaled

Transport in the Blood

• Oxygen and carbon dioxide.

Oxygenated Blood

• Blood rich in oxygen leaves the lungs and is pumped by the heart to the rest of the body through a network of blood vessels

Deoxygenated Blood

• Blood carrying carbon dioxide and other wastes returns to the heart and is then pumped to the lungs for gas exchange

Structure of the Lung

• Soft, pink, and spongy filled with tiny air sacs called alveoli that facilitate the exchange of gasses

Alveoli and Capillaries

• Alveoli are grapelike clusters of air sacs that provide a large surface area for gaseous exchange
• Each alveolus is surrounded by a dense network of capillaries.

Diffusion in the Lungs

• Diffusion is the movement of particles from an area of high concentration to an area of low concentration

Health Implications

• Problems with gaseous exchange can lead to severe health issues

Blood Circulation from the Lungs to the Heart

• Crucial for supporting cellular respiration, supplying cells with oxygen and nutrients, and removing carbon dioxide and waste products

Blood Circulation from the Heart to the Rest of the Body

• Circulates through the body via a network of arteries, capillaries, and veins

Arteries

• Function: Transport blood away from the heart
• Characteristics: carry oxygenated blood under high pressure

Capillaries

• Function: Connect arteries and veins, facilitating the exchange of oxygen
• Characteristics: thin, network around body cells to ensure efficient exchange

Veins

• Function: Transport blood back to the heart
• Characteristics: carry deoxygenated blood, have valves to prevent backflow

Respiration Within the Cells

• Cellular respiration occurs in the mitochondria of cells, where oxygen is used to convert glucose

The Human Body Requires a Variety of Nutrients and Substances To Perform Its Functions Effectively

• Obtained from the food we consume

The Seven Building Blocks of A Healthy Diet

• Proteins, carbohydrates, fats, vitamins, minerals, fiber, and water

Proteins

• Fundamental for building and repairing body cells and tissues
• Foods rich in protein include fish, meat, poultry, eggs, soybeans, peas, beans, nuts, and seeds

Carbohydrates

• The primary energy source for the body
• Foods high in carbohydrates include whole grain bread, potatoes, pasta, rice, fruits, vegetables, maize, and legumes

Fats and Oils

• Protect, insulate, transport, and provide energy

Vitamins

• Essential for various chemical reactions in the body
• Strengthen the immune system

Minerals

• Essential for various body functions
• Examples include calcium, iron, magnesium, sodium

Fibre

• Found in the skins of fruits and vegetables
• Helps maintain regular bowel movements

Water

• Composition of more than 50% water
• Helps blood carry nutrients and waste around the body
• Facilitates chemical reactions in cells

Testing Food

• Used to identify the types of food molecule present in different foods

Health Problems Related to Diet

• Poor dietary choices can lead to conditions such as obesity, malnutrition, and chronic diseases like diabetes and heart disease

Digestion Is A Vital Process That Transforms The Food We Eat Into Small Molecules That Can Be Absorbed and Transported To The Body's Cells

• Mechanical digestion and chemical digestion

Types of Digestion

• Mechanical digestion and chemical digestion

Mechanical Digestion

• Involves the physical breakdown of food

Chemical Digestion

• Involves digestive enzymes that break down food

The Alimentary Canal

• A continuous tube that runs from the mouth to the anus
• Includes the mouth, oesophagus, stomach, small intestine, large intestine, rectum, and anus

Mouth

• Mechanical and chemical digestion begins

Oesophagus

• A muscular tube that connects the mouth to the stomach

Stomach

• Continues the process of mechanical digestion through muscular contractions

Small Intestine

• The majority of digestion and nutrient absorption occurs here

Large Intestine (Colon)

• The primary function is to absorb water and salts from the remaining undigested food matter

Rectum And Anus

• The rectum stores feces until they are expelled through the anus

Key Processes In Digestion

• Peristalsis, enzymes and absorption

Peristalsis

• Muscle contractions that move food through the alimentary canal

Enzymes In Digestion

• Specific enzyme target different types of nutrients (i.e Amylase)

Absorption

• Nutrients from digested food are absorbed primarily in the small intestine