Life process
Nutrition
Humans need various nutrients for energy, growth, and health.
Nutrients include carbohydrates, proteins, lipids, vitamins, and minerals.
The human diet must include macronutrients (carbohydrates, proteins, lipids) and micronutrients (vitamins, minerals).
Carbohydrates are composed of carbon, hydrogen, and oxygen atoms in a 2:1 ratio.
Classified into monosaccharides, disaccharides, and polysaccharides.
Proteins are made of amino acids and have properties like denaturation and solubility.
Lipids are fats and oils with fewer oxygen atoms than carbohydrates.
Carbohydrates, Proteins, and Lipids
Carbohydrates have properties like reducing sugars, non-reducing sugars, and starch.
Proteins are composed of amino acids and have different structures like globular and fibrous.
Lipids are made up of fatty acids and glycerol, feel greasy, and are insoluble in water.
Tests for Nutrients
Laboratory tests can identify carbohydrates, proteins, and lipids.
Tests include Benedict’s solution for reducing sugars, iodine solution for starch, biuret test for proteins, and emulsion test for lipids.
Sources and Functions of Nutrients
Carbohydrates, proteins, and lipids provide energy and materials for growth and repair.
Carbohydrates from sugars and starch provide energy and storage.
Proteins from various sources help in cell growth, enzyme production, hormone regulation, and immunity.
Lipids from fats and oils are essential for cell membranes, energy, storage, and insulation.
Vitamins and minerals are required in small amounts for healthy growth and development.
Examples of important vitamins and minerals and their sources and functions are provided.
Vitamins and Minerals
Vitamin C
Sources: West Indian cherries, citrus fruits, raw green vegetables
Functions: Keeps tissues healthy, strengthens the immune system, helps absorb iron
Vitamin D
Sources: Oily fish, eggs, cod liver oil
Functions: Promotes calcium and phosphorus absorption, strengthens bones and teeth
Calcium
Sources: Dairy products, green vegetables
Functions: Builds and maintains healthy bones and teeth, helps blood clotting
Iron
Sources: Red meat, liver, eggs, beans, nuts
Functions: Makes haemoglobin for oxygen transport in red blood cells
Vitamin and Mineral Deficiency Diseases
Night blindness
Cause: Vitamin A deficiency
Symptoms: Poor vision in dim light, slow vision adaptation
Treatment: Increase vitamin A-rich foods, take supplements
Rickets (in children)
Cause: Vitamin D and/or calcium deficiency
Symptoms: Soft, weak, deformed bones
Treatment: Increase vitamin D and calcium intake, exposure to sunlight
Anaemia
Cause: Iron deficiency
Symptoms: Reduced red blood cells, pale complexion, tiredness
Treatment: Increase iron-rich foods, take supplements, increase vitamin C intake
Water
Importance: Essential for the body, acts as a solvent, aids in digestion and waste excretion
Dietary Fibre
Definition: Indigestible food, found in fruits, vegetables, and grains
Benefits: Adds bulk to food, stimulates peristalsis, prevents constipation and reduces cancer risk
Constipation and Diarrhoea
Constipation
Causes: Lack of dietary fibre, water, inactivity, stress
Effects: Bloating, abdominal pain, colorectal cancer risk
Diarrhoea
Causes: Infections, conditions like IBS, dehydration
Effects: Dehydration, electrolyte imbalance, malnutrition
Balanced Diet
Definition: Must contain carbohydrates, proteins, lipids, vitamins, minerals, water, and dietary fibre
Importance: Supplies energy, materials for growth, and maintains health
Energy Requirements
Factors affecting daily energy needs: Age, occupation, gender, activity level, pregnancy, breastfeeding
Malnutrition
Definition: Imbalance of nutrients in the diet
Types: Undernutrition, overnutrition
Consequences: Various serious conditions
Obesity
Definition: Excessive fat accumulation in the body
Causes: Excessive consumption of energy-rich foods, lack of physical activity
Risks: Hypertension, heart disease, diabetes, cancers
Nutrition Disorders
Anorexia
Serious mental health condition
Person keeps body weight low by eating very little, vomiting, using laxatives, and excessive exercise
Mainly affects girls and young women
Can lead to death
Bulimia
Eating disorder and mental health condition
Involves cycle of binge eating followed by purging
Person eats large quantities of food quickly and induces vomiting or takes laxatives
Protein-energy malnutrition (PEM)
Includes kwashiorkor and marasmus
Caused by inadequate protein or energy intake
Affects young children in developing countries
Kwashiorkor
Symptoms: loss of muscle mass, oedema, changes in skin and hair pigmentation
Marasmus
Symptoms: low body weight, thin face, visible ribs and shoulders, dry skin
Body mass index (BMI)
Indicator of body fat
Calculated using weight and height
Categories: underweight, healthy weight, overweight, obese, severely obese
Teeth and Digestion
Importance of Teeth
Break food into smaller pieces for easier digestion
Larger surface area for enzymes to act on
Easier swallowing
Types of Teeth
Incisors, canines, premolars, molars
Milk teeth and permanent teeth
Functions of each type of tooth
Tooth Structure
Crown and root parts
Covered with enamel and cement
Internal structure includes dentine, pulp cavity, nerves, and blood vessels
Enamel: non-living, covers the crown, hardest substance in the body, resistant to chipping and decay
Dentine: bone-like, supports enamel, protects pulp
Pulp Cavity: composed of living cells, nerves, and gum
Cement: bone-like, covers the root
Periodontal Membrane: anchors the root in the jawbone
Functions of Tooth Parts
Enamel: protects against decay, insulates against hot/cold, provides chewing surface
Dentine: forms bulk, supports enamel, protects pulp
Pulp Cavity: supplies living cells with nutrients, nerves sensitive to pain
Cement: covers dentine in the root
Periodontal Membrane: anchors root, allows slight movement for shock absorption
Tooth Decay
Caused by bacteria, saliva, and food forming plaque
Acid in plaque eats away enamel and dentine, leading to cavities and infections
Progresses from no toothache to severe toothache and abscess formation
Causes of Tooth Decay
High sugar/starch content in food, sugary/acidic drinks
Poor oral hygiene, lack of fluoride, teeth grinding, smoking
Guidelines for Dental Care
Proper brushing and flossing, fluoride toothpaste, dental visits
Avoid sugary foods/drinks, use mouthwash, maintain oral hygiene
Chemical Digestion of Food
Large food molecules broken down by hydrolysis with digestive enzymes
Enzymes are biological catalysts, specific to reactions, work best at optimum temperature and pH
Properties of Enzymes
Enzymes are specific, work best at optimum temperature and pH
High temperatures denature enzymes, extremes of pH denature most enzymes
Enzyme action aided by vitamins/minerals, inhibited by poisons
Digestive Enzymes
Categories: Carbohydrases (polysaccharides to monosaccharides), Proteases (proteins to amino acids), Lipases (lipids to fatty acids/glycerol)
Digestive System and Chemical Digestion
Summary of the process involving mouth, teeth, salivary glands, liver, gall bladder, pancreas, stomach, small intestine, and colon
Human Digestive System
Structures and functions from mouth to anus, including organs like liver, pancreas, stomach, and small intestine
Summary of Chemical Digestion
Mouth
Saliva from salivary glands
Water and mucus
Salivary amylase
Functions:
Moisten and lubricate food
Begins digestion of starch into maltose
Stomach
Gastric juice from cells in the stomach wall
Hydrochloric acid
Rennin
Pepsin
Functions:
Maintains pH for pepsin and rennin
Begins digestion of protein into peptides
Small Intestine
Bile from liver cells
Bile pigments and organic bile salts
Pancreatic juice from pancreas cells
Pancreatic amylase, trypsin, pancreatic lipase
Intestinal juice from small intestine walls
Maltase, sucrase, lactase, peptidase
Functions:
Emulsify lipids
Continue digestion of starch, protein, and lipids
Movement and Absorption
Movement of Food
Peristalsis moves food through the alimentary canal
Absorption in Small Intestine
Products absorbed through ileum lining into blood capillaries and lacteals
Substances absorbed include monosaccharides, amino acids, fatty acids, glycerol, vitamins, minerals, and water
Villi and microvilli increase surface area for absorption
Absorption in Colon
Undigested food passes to colon for water and mineral absorption
Waste becomes solid as water is absorbed
Egestion
Removal of undigested food as faeces through anus
Assimilation
Liver converts monosaccharides to glucose for energy or storage
Amino acids used for protein synthesis, enzyme production, hormone creation, and antibodies
Excess amino acids converted to urea for excretion
Egestion and Assimilation
Absorption in Colon
Undigested food in colon absorbs water and mineral salts
Egestion
Removal of undigested food as faeces through anus
Assimilation
Body uses absorbed food molecules for various functions
Monosaccharides converted to glucose for energy or storage as fat
Amino acids used for protein synthesis, enzyme production, hormone creation, and antibodies
Excess amino acids converted to urea for excretion
Fatty acids and glycerol
Carried by lymph to general circulation
Used to make cell membranes of newly forming cells
Used by body cells in respiration under certain circumstances
Excess converted to fat and stored in adipose tissue
The respiratory system
Energy obtained from food through respiration
Importance of breathing and gaseous exchange
Gaseous exchange surfaces and their adaptations
Structure of the human respiratory system
Lungs, bronchioles, alveoli, pleural membranes, bronchus, trachea, larynx, pharynx, diaphragm
Functions of nasal cavities, epiglottis, larynx, trachea, bronchi, bronchioles, alveoli
Structure of the human thorax
Components like diaphragm, larynx, trachea, bronchioles, pleural membranes, capillaries
Functions of nasal cavities, epiglottis, larynx, trachea, bronchi, bronchioles, alveoli
Structure and Functions of the Respiratory System
Pleural membranes and pleural fluid
Form an airtight cavity between lungs and rib-cage/diaphragm
Allows volume changes in chest cavity to affect lung volume
Pleural fluid acts as a lubricant during breathing
Intercostal muscles and diaphragm
Contract and relax to change chest cavity/lung volume
Facilitate air movement in and out of lungs
Mechanism of Breathing and Gaseous Exchange
Breathing involves intercostal muscles and diaphragm
Air warmed, cleaned, and moistened during inhalation
Gaseous exchange occurs in alveoli between air and blood
Alveoli characteristics: pocket shape, thin wall, rich blood supply, lined with moisture
Gaseous Exchange in Alveolus
Composition of Air and Blood
Exhaled air: 16% O2, 4.0% CO2; Inhaled air: 21% O2, 0.04% CO2
Deoxygenated blood: low O2, high CO2; Oxygenated blood: high O2, low CO2
Factors Affecting Breathing Rate
Normal breathing rate: 12-16 breaths/min for a healthy adult at rest
Medulla of the brain controls breathing rate based on CO2 levels
Factors increasing breathing rate: exercise, stimulant drugs, smoking, anxiety, environmental factors
Factors decreasing breathing rate: rest, depressant drugs, fresh air, environmental factors
Vital Capacity and Mouth-to-Mouth Resuscitation
Vital Capacity
Maximum exhaled air volume after deep inhalation
Indicates lung function and presence of lung disease
Depends on age, gender, body size, and fitness
Mouth-to-Mouth Resuscitation
Technique to supply oxygen to a non-breathing person
Steps involved in performing mouth-to-mouth resuscitation
Effects of Smoking Cigarettes
Nicotine Addiction
Nicotine is addictive, causing smokers to continue smoking
Reduces oxygen carrying capacity of blood, affecting respiration and exercise
Lung Damage
Increased mucus production, cilia paralysis, chronic bronchitis
Inflammation of bronchi/bronchioles, obstructed airways, emphysema
Cancer Risk
Components in cigarette smoke are carcinogenic
Lead to mutations in respiratory cells, causing cancerous tumors
Chronic Bronchitis and Emphysema
Types of Chronic Obstructive Pulmonary Disease (COPD) caused by smoking
Respiration
Respiration is the process of releasing energy from food in living cells.
Catalyzed by enzymes and occurs in multiple stages.
ATP is the energy currency of cells.
Formed by combining energy with ADP and a phosphate group.
Functions of ATP in cells include manufacturing molecules, cell growth, repair, and active transport.
Aerobic respiration uses oxygen and occurs in mitochondria, producing CO2, water, and 38 ATP.
Anaerobic respiration occurs without oxygen, producing less energy and various byproducts.
Examples of anaerobic respiration include yeast fermentation and muscle cells during strenuous exercise.
Industrial and Domestic Uses of Anaerobic Respiration
Yeast cells ferment sugars to produce ethanol, CO2, and 2 ATP for making bread and alcoholic beverages.
Certain bacteria ferment lactose in milk to produce lactic acid for making yogurt.
Bacteria break down organic matter anaerobically to produce biogas.
Oxygen debt occurs in muscle cells during strenuous exercise, leading to lactic acid buildup and fatigue.
The Circulatory System
The circulatory system transports substances between body surfaces and cells.
Humans have a transport system due to small surface area to volume ratio and limitations of diffusion.
Materials transported include oxygen, water, nutrients, waste products, and heat.
Components of the cardiovascular system are blood, blood vessels, and the heart.
Blood consists of red blood cells, white blood cells, platelets, and plasma.
Overall, the text covers the processes of respiration, including aerobic and anaerobic respiration, as well as the industrial and domestic uses of anaerobic respiration. It also touches on the circulatory system and its components, emphasizing the importance of transporting substances efficiently in the human body.
Plasma Composition and Functions
Plasma is 90% water and 10% dissolved substances.
Includes products of digestion, waste products, hormones, and plasma proteins.
Functions of plasma involve transporting various substances like products of digestion, carbon dioxide, urea, hormones, and heat.
Blood Cells
Red Blood Cells (Erythrocytes)
Structure: Biconcave discs with no nucleus, rich in haemoglobin.
Formation: Produced in red bone marrow, broken down in the liver and spleen.
Functions: Transport oxygen as oxyhaemoglobin and small amounts of carbon dioxide.
White Blood Cells (Leucocytes)
Types: Lymphocytes and Phagocytes.
Functions: Produce antibodies, antitoxins, and engulf pathogens.
Formation: Develop in red bone marrow and mature in organs like lymph nodes and spleen.
Platelets (Thrombocytes)
Structure: Cell fragments with no nucleus.
Functions: Help blood clotting at wounds.
Formation: Formed from cells in red bone marrow.
Blood Clotting
Process involves platelets plugging the cut, conversion of prothrombin to thrombin, and fibrinogen to fibrin.
Importance: Prevents blood loss and entry of pathogens.
Blood Groups
Classified based on antigens on red blood cells.
Two grouping systems: ABO system (A, B, AB, O) and rhesus system (positive, negative).
Blood Vessels
Types: Arteries, capillaries, and veins.
Arteries carry blood away from the heart, capillaries link arteries to veins, and veins transport blood back to the heart.
Differences in pressure, flow, oxygenation, and structure among arteries, capillaries, and veins.
The Heart
The heart is composed of cardiac muscle that contracts myogenically.
Divided into four chambers: two atria and two ventricles.
Atria collect blood from vena cavae and pulmonary veins, while ventricles pump blood out via pulmonary artery and aorta.
Valves ensure one-way blood flow.
The Heart’s Pacemaker
Sinoatrial node in the right atrium produces electrical impulses for heart contraction.
Rate can be modified by nerve impulses or adrenaline.
Artificial pacemaker regulates heartbeat if necessary.
Cardiac Cycle
Involves diastole, atrial systole, and ventricular systole.
Blood pressure is measured in mm Hg and ideal range is 90/60 mm Hg to 120/80 mm Hg.
Circulation
Double circulation: pulmonary circulation and systemic circulation.
Pulmonary circulation: blood travels to lungs to become oxygenated.
Systemic circulation: blood travels to body organs to supply oxygen.
Blood Pressure
High blood pressure (hypertension) is 140/90 mm Hg or above.
Can be caused by various factors.
Major Blood Vessels
Illustration of major blood vessels in the human body.
Causes and Effects of Heart Attacks
Atherosclerosis is the main cause of heart attacks.
Fatty deposits in coronary arteries lead to blockages.
Risk factors for heart attacks include hypertension, obesity, smoking, diet, and alcohol consumption.
Heart Attack and Lymphatic System
Symptoms of a heart attack:
Chest pain or discomfort
Upper body pain or discomfort
Shortness of breath
Feeling weak, lightheaded, or dizzy
Lymphatic system components:
Lymph as the transporting medium
Lymph vessels with valves and lymph nodes
Lymphocytes and phagocytes in lymph nodes
Functions of the lymphatic system:
Removal of cellular waste
Draining excess tissue fluid
Maintaining blood volume and pressure
Defending the body against pathogens
Absorbing fatty products of digestion in lacteals
Functions of Lymph Nodes
Functions of lymph nodes:
Destroying pathogens in lymph
Filtering dead and cancerous cells
Releasing lymphocytes during infections
Skeletal System
Human skeletal system:
Made of 206 bones held by ligaments
Composed of bone and cartilage
Bone and cartilage:
Bone: living cells with calcium phosphate and collagen
Cartilage: living cells with collagen, elastic and flexible
Importance of cartilage:
Reducing friction at joints
Aiding in shock absorption
Maintaining shape of certain body parts
Axial and appendicular skeleton:
Axial: skull, vertebral column, ribs, sternum
Appendicular: limbs, pectoral and pelvic girdles
Conclusion
The heart attack symptoms include chest pain, upper body discomfort, shortness of breath, weakness, and dizziness.
The lymphatic system functions in waste removal, fluid drainage, blood volume maintenance, pathogen defense, and fat absorption.
The skeletal system supports movement, protects organs, and consists of bones and cartilage.
Vertebral Column and Ribs
Vertebral column consists of 33 vertebrae, supporting the body and protecting the spinal cord.
Ribs are attached dorsally to the vertebral column and ventrally to the sternum, forming the rib cage.
Rib movement is crucial for breathing.
Appendicular Skeleton
Comprised of pectoral girdle, pelvic girdle, arms, and legs.
Girdles connect limbs to the axial skeleton, providing attachment points for muscles.
Limbs have long bones with joints for movement and muscle attachment.
Structure of Limbs
Arms and legs follow the pentadactyl limb pattern.
Detailed structure of the humerus bone, including spongy and compact bone components
Functions of the Skeleton
Movement facilitated by jointed skeleton and muscles.
Protection of internal organs by skull, vertebral column, rib cage, and sternum.
Support for soft body parts by vertebral column, pelvic girdle, and legs.
Breathing mechanism involving rib cage movements.
Production of blood cells in red bone marrow.
Tendons and Ligaments
Tendons attach muscles to bones, while ligaments connect bones at joints.
Tendons are non-elastic and transmit muscle force to bones.
Ligaments are elastic, holding bones together and allowing slight movement at joints.
Movement by Skeletal Muscles
Skeletal muscles are bundles of muscle fibers surrounded
Joints
A joint is where two bones meet.
Three types of joints: fixed, partially movable, and moveable.
Moveable joints have hinge and ball and socket types.
Movement of a limb
Muscle contraction causes movement.
Antagonistic muscle pairs are needed for movement.
Structure of joints
Hinge joint structure includes capsule, synovial membrane, synovial fluid, and articular cartilage.
Ball and socket joint structure includes femur/pelvic girdle and articular cartilage.
Muscle attachment
Muscles are attached by tendons to bones.
Origin and insertion points of muscles.
Movement of the elbow joint
Biceps and triceps muscles move the elbow joint.
Biceps is the flexor muscle, and triceps is the extensor muscle.
Effects of exercise on the skeletal system
Improves muscle tone, synovial fluid production, ligament strength, muscle tissue growth, and bone density.
Factors affecting the skeletal system
Poor posture strains muscles and affects organ function.
Poor footwear can lead to posture issues and joint problems.
Obesity and unbalanced diet impact bone health.
Importance of locomotion
Locomotion is essential for various human activities.
Excretion and Homeostasis
Excretion Process
Removal of waste and harmful substances produced by chemical reactions in body cells
Importance of excretion:
Prevents toxic metabolic waste buildup
Helps maintain a constant internal environment
Metabolic Waste Produced by Humans
Carbon dioxide, water, urea, bile pigments, and heat
Excretory Organs
Kidneys, lungs, skin, and liver
Role of Kidneys
Excrete urea and regulate blood plasma volume and concentration
Structure of kidneys: cortex, medulla, pelvis
Structure of Urinary System
Components: kidneys, ureter, bladder, urethra, sphincter muscle
Kidney composed of nephrons producing urine
Nephron Structure
Bowman’s capsule, convoluted tubules, loop of Henle
Arteriole, glomerulus, capillaries, venules
Urinary System Function
Ultra-filtration and selective reabsorption in nephrons
Production and flow of urine
Urine Production in Nephrons
Processes: ultra-filtration and selective reabsorption
Filtrate composition: glucose, amino acids, water, salts, urea
Renal Dialysis
Treatment for kidney failure
Process of removing waste from blood using a dialysis machine
The Skin
Largest organ in the human body
Composed of epidermis, dermis, and subcutaneous layer
Skin Structure
Epidermis consists of three layers: cornified layer, living layer, and malpighian layer.
Protects against pathogens, water loss, UV rays, and chemicals.
Sebaceous glands secrete sebum to keep skin soft and inhibit bacteria growth.
Nerve endings detect touch, pressure, pain, and temperature.
Hairs and hair erector muscles cause goosebumps for insulation.
Sweat glands produce sweat for cooling the body.
Subcutaneous layer protects against heat loss and acts as padding.
Homeostasis
Maintaining a constant internal environment is crucial.
Negative feedback mechanisms involve the nervous system and hormones.
Receptors detect changes and effectors respond to return levels to normal.
Failure in corrective mechanisms can lead to health issues like diabetes.
Osmoregulation
Regulates water content in body fluids to prevent cell damage.
Kidneys control water reabsorption to maintain fluid balance.
Factors like drinking habits and sweating affect water concentration.
Osmoregulation and Body Temperature Regulation
Osmoregulation ensures proper water balance in the body.
Body temperature regulation is vital for enzyme function.
Heat gain from metabolic processes and heat loss through skin mechanisms.
Hypothalamus detects temperature changes and triggers appropriate responses.
Heat, Temperature, and Blood Regulation
Heat is the total energy in an object, while temperature measures hotness or coldness.
Carbon dioxide levels affect blood acidity and are controlled by breathing adjustments.
Pancreas secretes insulin and glucagon to regulate blood glucose levels.
Insulin helps cells absorb glucose, while glucagon converts stored glycogen to glucose.
Blood Glucose Control and Diabetes
Pancreas secretes hormones to maintain blood glucose levels.
Diabetes mellitus occurs when blood glucose levels are unregulated.
Excretion
Definition: Process of removing waste products from the body.
Egestion vs. Excretion
Egestion is not considered excretion because it involves the removal of undigested food, not metabolic waste.
Importance of Excretion
Without excretion, toxic waste would accumulate in the body, leading to organ damage and eventually death.
Excretory Organs in Human Body
Table showing different excretory organs and what each excretes.
Urine Production in Kidneys
Outline of how urine is produced in Marissa's kidneys.
Dialysis for Kidney Failure
Explanation of why dialysis for kidney failure needs to occur at regular intervals.
Skin Structures and Functions
Functions of the epidermis, subcutaneous layer, and sebaceous glands.
Homeostasis
Definition and importance of negative feedback mechanisms in maintaining internal balance.
Regulation of Water Content
Process for regulating water content in body fluids.
Effects of Heat and Temperature
Difference between heat and temperature, and changes in the skin when body temperature rises above 37°C.
Blood Glucose Regulation
Mechanism by which the body returns blood glucose levels to normal after a carbohydrate-rich meal.
Coordination and Control
Importance of monitoring the environment and responding through the nervous and endocrine systems.
Definitions
Stimulus, response, receptor, and effector explained.
Coordination by Nervous and Endocrine Systems
Receptors detecting stimuli and effectors responding, with the nervous system and endocrine system involved.
Comparison of Nervous and Endocrine Systems
Differences in how messages are carried, speed, precision, and duration of effects.
Human Nervous System
Composition of the central nervous system (CNS) and peripheral nervous system (PNS).
Parts of the Brain
Functions of the cerebrum, cerebellum, medulla oblongata, hypothalamus, and pituitary gland.
Neurones
Types of neurones: sensory, motor, and relay; their structures and functions.
Brain Parts and Functions
Description of the main parts of the human brain and their respective functions.
Neurones Structure
Components of neurones: dendrites, axons, myelin sheath, and nerve fibres.
Properties of Neurones
Irritability and conductivity as major properties of neurones.
Structure of Sensory and Motor Neurones
Detailed structures of sensory and motor neurones, including dendrites, axons, myelin sheath, and cell bodies.
Connection Between Receptor and Effector
Illustration of the connection between a receptor and an effector through neurones.
Neurones Properties
Key properties of neurones: irritability and conductivity.
Nerves
Nerves are cordlike bundles of nerve fibers surrounded by connective tissue.
Impulses pass between the CNS and the rest of the body through nerves.
Types of nerves:
Sensory nerves (afferent nerves) carry impulses from receptors to the CNS.
Motor nerves (efferent nerves) carry impulses from the CNS to effectors.
Mixed nerves carry impulses in both directions.
Classification based on connection to CNS:
Cranial nerves connect to the brain.
Spinal nerves connect to the spinal cord.
Synapses
Adjacent neurones communicate through synapses.
Tiny gaps between synaptic knobs and dendrites/cell body.
Neurotransmitters released into synapses by vesicles.
Ensure impulses travel in one direction.
Allow interconnection of many neurones.
Voluntary Actions
Controlled by the cerebrum of the brain.
Initiated consciously in two ways:
Coordinating incoming information from sensory neurones.
Spontaneously initiating an action without incoming information.
Impulses sent from the cerebrum to motor neurones in the brain and spinal cord.
Characteristics of voluntary actions:
Learned, relatively slow, complex.
Involuntary Actions
Actions that occur without conscious thought.
Characteristics:
Not learned, rapid, simple.
Involuntary Actions Types
Autonomic nervous system controls internal organs.
Regulates functions like breathing rate, heart rate, and digestion.
Reflex actions are rapid, automatic responses to stimuli.
Always initiated by an external stimulus.
Reflex arc components:
Receptor, sensory neurone, relay neurone, motor neurone, effector.
Classified as cranial reflexes or spinal reflexes.
Cranial Reflexes
Impulses pass through cranial nerves and the brain.
Examples: pupil reflex, blinking, sneezing, coughing.
Spinal Reflexes
Impulses pass through spinal nerves and the spinal cord.
Examples: knee jerk reflex, withdrawal reflex in response to pain.
Sense Organs and the Eye
Sense organs have specialized receptor cells detecting stimuli
Receptor cells turn stimuli into electrical impulses
Impulses travel to the CNS for interpretation by the cerebrum
Sense organs in the human body include eyes, ears, nose, tongue, and skin
Each organ has specialized receptor cells and detects specific stimuli
The eye detects light, converts it into nerve impulses, and transmits them to the brain
Various parts of the eye like lens, pupil, cornea, and retina have specific functions
The brain interprets impulses from the eye to form a precise picture of the object
Image Formation and Light Detection
Light rays must be refracted to form a clear image on the retina
Cornea and lens refract light rays to focus them on the retina
The retina has rods and cones for detecting light intensity and color
Rods function in low light, cones in high light for color detection
Control of light entering the eye is regulated by the size of the pupil
Iris muscles control pupil size based on light intensity
Sight Defects and Corrections
Short-sightedness (myopia) causes distant objects to be out of focus
Corrected by wearing diverging (concave) lenses
Accommodation is the process of changing the lens shape to focus light onto the retina
Ciliary muscles in the ciliary body bring about accommodation
These sections cover the functioning of sense organs, particularly the eye, in detecting stimuli, forming images, detecting light intensity and color, controlling light entry, and correcting sight defects like short-sightedness through accommodation.
Eye Conditions
Long-sightedness (hypermetropia)
Distant objects clear, near objects out of focus
Caused by short eyeball or flat lens
Corrected by converging lenses
Old sight (presbyopia)
Difficulty seeing near objects due to aging
Corrected by converging lenses
Astigmatism
Both near and distant objects appear blurry
Caused by unevenly curved cornea or lens
Corrected by unevenly curved lenses
Glaucoma
Increased eye fluid pressure, can lead to blindness
Treated with eye drops, laser treatment, or surgery
Cataract
Cloudy lens leading to blurred vision
Corrected by surgery to replace the lens
Endocrine System
Endocrine System
Composed of endocrine glands secreting hormones into blood
Main Endocrine Glands
Pituitary, thyroid, adrenal, pancreas, ovary, testis
Hormones and Functions
Pituitary: ADH, GH, FSH, LH
Thyroid: Thyroxine
Adrenal: Adrenaline
Pancreas: Insulin, Glucagon
Endocrine Glands and Hormones
Ovaries
Oestrogen: Controls female secondary sexual characteristics
Progesterone: Regulates menstrual cycle
Placenta during Pregnancy
Progesterone: Maintains uterus lining, stimulates breast gland growth
Testes
Testosterone: Controls male reproductive organs and characteristics
Reproductive System
Asexual vs Sexual Reproduction
Asexual Reproduction
Involves one parent and offspring are genetically identical.
Rapid process without gamete production or fertilization.
Common in unicellular organisms, fungi, plants, and some animals.
Sexual Reproduction
Involves two parents and offspring show variation.
Slower process involving gamete production, fertilization, and embryo development.
Female Reproductive System
Components
Ovary, uterus, cervix, vagina, fallopian tube, uterus lining.
Functions of each part in ovum production, fertilization, and embryo implantation.
Male Reproductive System
Components
Testes, scrotum, epididymis, foreskin, seminal vesicle, prostate gland, urethra, vas deferens, penis.
Functions of each part in sperm production, storage, and ejaculation.
Production of Ova and Sperm
Ova Production
Monthly maturation process from puberty to menopause.
Ovulation releases mature ovum for potential fertilization.
Sperm Production
Continuous production from puberty in the seminiferous tubules.
Stored in the epididymis until ejaculation.
Cancers of Reproductive Systems
Types of Cancers
Ovarian, cervical, uterine, breast, prostate, testicular.
Symptoms, detection methods, and treatments for each type of cancer.
Menstrual Cycle
Cycle Overview:
Consists of ovulation and menstruation.
Ovulation: Release of an ovum from an ovary.
Menstruation: Loss of the uterus lining if fertilization doesn't occur.
Hormones Involved:
FSH: Stimulates ovum development and oestrogen production.
Oestrogen: Thickens uterus lining and stops FSH secretion.
LH: Causes ovulation and corpus luteum development.
Progesterone: Maintains uterus lining thickness.
Cycle Phases:
Ovum matures in Graafian follicle.
Ovulation occurs around day 14.
Corpus luteum develops and breaks down.
Uterus lining thickens, remains thick, then breaks down.
Bringing Sperm and Ova Together
Sperm and Ova Union:
Erection of penis during sexual excitement.
Sperm ejaculated into the vagina, swim to fallopian tubes.
Fertilization to Birth:
Fertilization: Fusion of ovum and sperm nuclei to form a zygote.
Implantation: Zygote divides into an embryo, implants in the uterus lining.
Pregnancy and Development:
Embryo develops into a foetus.
Placenta forms, facilitates exchange of materials between mother and embryo.
Umbilical cord connects embryo to placenta for nutrient exchange.
Development of Human Embryo/Fetus
Embryo/ Fetus Development:
Various stages from a hollow ball of cells to a fully developed fetus.
Gestation period lasts around 40 weeks.
Birth Process:
Labour initiated by oxytocin, leading to contractions.
Baby delivered headfirst, umbilical cord cut, placenta expelled.
Effect of Pregnancy on Menstrual Cycle:
Corpus luteum and placenta secrete progesterone to maintain uterus lining thickness and inhibit menstruation.
Prenatal and Postnatal Care
Prenatal Care:
Essential for normal fetal growth and mother's health.
Includes regular checkups and a balanced diet rich in nutrients.
Postnatal Care:
Important for the health and well-being of the newborn and mother after birth.
Prenatal Care
Avoid drugs like alcohol, cigarettes, and illegal drugs to protect the developing fetus.
Exercise regularly for fitness.
Attend prenatal classes to learn correct exercises, breathing rhythms, and baby care.
Postnatal Care
Breastfeed newborn for at least 6 months for nutrients, antibodies, and emotional bond.
Keep baby warm, clean, interact with parents, surroundings, and regular checkups.
Vaccinate against diseases, wean onto solid food, and provide continual care and teaching.
Mother's Care
Maintain a balanced diet, avoid drugs, exercise regularly, and receive physical and emotional support.
Birth Control Methods
Abstinence
Refrain from sexual intercourse, completely effective, and protects against STIs.
Withdrawal
Penis withdrawn before ejaculation, unreliable, relies on self-control.
Rhythm Method
Intercourse restricted to ovulation times, unreliable due to ovulation time variations.
Spermicides
Kill sperm, easy to use, but not reliable alone and may cause irritation.
Condom
Barrier method, reliable if used correctly, protects against STIs, may reduce sensitivity.
Diaphragm
Barrier method, fairly reliable, easy to use, may slip out of place if not fitted properly.
Intra-uterine Device (IUD)
Prevents sperm reaching ova, very reliable, few side effects, must be inserted by a doctor.
Contraceptive Pill
Hormone pill, prevents ovulation, almost totally reliable if taken daily, may cause side effects.
Importance of Family Planning
Helps in deciding the number of children and spacing between births.
Benefits include more time and care for each child, better education, and cost savings.
Enables parents to choose when to have a family, considering career and education.
Reduces health risks to women from unintended pregnancies and unsafe abortions.
Allows women to participate fully in society and advance in the workplace.
Global perspective on population growth:
Rapid population growth leads to shortages of resources, pollution, and decreased living standards.
Family planning can help reduce population growth and improve living standards.
Arguments for induced abortion:
Health risks to mother or fetus.
Severe genetic abnormalities in the fetus.
Pregnancy resulting from rape.
Preventing unwanted children.
Arguments against induced abortion:
Can lead to irresponsible behavior.
Medical complications and infertility risks.
Impact on mental health and considered murder by some.
Breastfeeding and Baby Development
Breast Milk as Complete Food
Breast milk is considered complete due to its balanced nutrition for infants.
Digestion Process
Breast milk is digested in Jay's digestive system through enzymes and absorption.
Weight Gain Difference
Babies fed on powdered milk may gain weight faster due to different nutrient compositions.
Baby's Teething and Tooth Enamel
Teeth Development
Jay needs teeth to properly chew and break down solid foods.
Importance of Tooth Enamel
Enamel being the hardest substance protects teeth from wear and tear.
Homeostasis and Body Responses
Homeostasis Definition
Homeostasis is the body's ability to maintain internal stability.
Negative Feedback
Negative feedback mechanisms help regulate body functions to maintain balance.
Body Heat Conservation
Body responds to cold by shivering to generate heat and constricting blood vessels to conserve heat.
Breathing Changes and Eye Focus
Breathing Changes
Increased breathing after exercise helps in oxygen intake and carbon dioxide removal.
Eye Focus Changes
Aging may cause difficulty in focusing due to changes in the lens; corrective measures may include glasses.
Nervous System vs. Endocrine System
Differences
Nervous system: Fast responses, short-lived effects; Endocrine system: Slower responses, longer-lasting effects.
Eye Changes and Pituitary Gland
Changes in eye focus due to aging may be related to pituitary gland function.
Menstrual Cycle and Pregnancy
Menstrual Cycle
Ovaries release eggs, uterus prepares for implantation, and shedding of the uterine lining occurs.
Hormones and Menstrual Cycle
Hormones like estrogen and progesterone regulate the menstrual cycle.