Human Muscular System

Muscles

• There are three types of muscles in the body: skeletal, cardiac, and smooth muscles.
• Skeletal muscles are attached to bones through tendons and have voluntary movement.
• Skeletal muscle structure is composed of bundles of muscle fibers, each containing tubules called myofibrils made of actin and myosin proteins.
• The arrangement of myofibrils creates striated skeletal muscle.
• Skeletal muscles serve various functions, including movement, support, and homeostasis.
• Examples of skeletal muscle conditions include muscular dystrophy, carpal tunnel syndrome, and myasthenia gravis.

Lever Systems

• Lever systems in the body consist of muscles, bones, and joints that provide a mechanical advantage.
• There are four parts of a lever system: a lever (bone), pivot/fulcrum (joint), effort (force generated by muscle contraction), and load (weight moved by the lever).
• The strength of a lever system increases as the force is moved farther away from the load.
• There are three types of lever systems: first-class, second-class, and third-class levers.
• Examples of lever systems in the body include the atlanto-occipital joint (first-class), plantar flexion (second-class), and elbow flexion (third-class).

Basal Metabolic Rate (BMR)

• BMR is the minimum amount of calories required for basic functions at rest.
• BMR is different from Resting Metabolic Rate (RMR).
• Harris and Benedict first published an equation for BMR, which was later revised by Mifflin-St. Jeor.
• BMR is dependent on factors such as temperature, gender, age, and genetics.
• A respirometer can measure an animal's BMR.

Connective Tissue

• Connective tissue supports, protects, and gives structure to other tissues in the body.
• Fibrous connective tissue is composed of sturdy, flexible collagen fibers.
• Types of fibrous connective tissue include ligaments, tendons, and fasciae.
• The Achilles tendon is the largest and strongest tendon in the body.

Glutamine

• Glutamine is one of the 11 non-essential amino acids produced by the human body.
• Glutamine is important during pregnancy, lactation, neonatal growth, and recovery from trauma and chronic illness.
• Glutamine has two amino groups, making it a nitrogen donor and carrier.
• Glutamine is found in dietary sources such as eggs, legumes, and meat products.
• Glutamine deficiency can lead to higher mortality and morbidity rates.

Digestion

• Digestion begins in the mouth and is the breakdown and absorption of food in the body.
• Saliva is a clear liquid produced by salivary glands that contains enzymes to initiate digestion.
• The alimentary canal is the long tube where food passes through and wastes are eliminated.
• Mouth infections can occur if saliva production is inadequate.

Vision

• Photoreceptors (rods and cones) in the retina convert light into electrical signals.
• The optic nerve transmits information from the retina to the brain.
• The brain processes the information to form a picture of what is seen.

Hearing

• The external ear collects sound vibrations and directs them inward.
• The ear canal, or auditory canal, is responsible for collecting sound vibrations.
• The shape and structure of the ear canal amplify and provide details about the vibrations.
• The eardrum, or tympanic membrane, begins to vibrate when air vibrations meet it.
• The vibrations are transferred to the inner ear and become liquid vibrations.
• The cochlea is a tiny curled fluid-filled structure that absorbs the vibrations.
• The movement of microscopic hairs in the cochlea stimulates nerves, creating an electrical signal that travels to the brain.

Cornea

• The cornea is the outermost surface of the eye.
• It is made up of six layers, each serving different functions.
• Minor and severe medical conditions can affect the cornea.
• While minor conditions can be treated with the cornea's self-repair mechanisms, more severe conditions can lead to permanent damage.

Sensitivity to Sound

• Increased sensitivity to sound can be caused by various factors, including fatigue, stress, anxiety, or medical conditions.
• Damage to the facial nerve or brain can lead to increased sensitivity to sound.
• Conditions such as depression, post-traumatic stress disorder, or Williams syndrome may also contribute to increased sensitivity.
• Stress or anxiety can also cause increased sensitivity to sound.

Virology

• Virology is the scientific study of viruses.
• Viruses are small collections of genetic coding with DNA or RNA surrounded by a protective protein coat.
• Viruses can be either small (17 nanometers to 1.5 micrometers) or giant (700 to 1000 nanometers in length).
• Viruses are not considered living because they are not able to reproduce on their own and are metabolically inert.
• Viruses depend on host cells to reproduce and continue infection.

Infections

• Infections are caused by external harmful agents, called pathogens, that invade and cause illness in the body.
• Examples of pathogens include viruses, bacteria, parasites, and prions.
• Infectivity is determined by how effectively a pathogen can cause an infection.
• Diseases are illnesses that arise from perturbations in bodily or biological functions.
• Infectious diseases are caused by pathogens, while noninfectious diseases have different etiologies.

Disordered Eating

• Disordered eating is a pathological and unhealthy pattern to eating.
• Disordered eating can progress to bulimia nervosa, which is an eating disorder.
• Bulimia nervosa is characterized by binge eating and compensatory behavior.
• There are two main subtypes of bulimia nervosa: purging and non-purging.

Dyspnea

• Dyspnea is labored or difficult breathing.
• Dyspnea can be caused by allergic reactions, lung and heart disease, and foreign body aspiration.
• Treatments for dyspnea focus on the underlying disease and may require medical assistance.

Anesthesia

• Anesthesia is medicine used to subdue a patient during medical procedures.
• Anesthesia can be classified into local, regional, and general anesthesia.
• General anesthesia has multiple stages, including the REM stage and the surgical stage.
• Side effects of general anesthesia include lingering numbness, nausea, and fatigue.
• A rare but serious risk of general anesthesia is malignant hyperthermia.

Analgesics

• Analgesics are drugs used to accomplish a state of analgesia, or pain relief.
• Analgesic drugs can be broken down into several groups, based on their uses and functions.
• Examples of analgesic groups include NSAIDs, COX-2 inhibitors, and opioids.

Analgesia

• Analgesia is the relief or reduction of pain through the use of analgesics.
• Analgesics can be classified into OTC medications and opioids.
• Anesthesia is different from analgesia, as it refers to the loss of sensation or even consciousness.
• There are two types of anesthesia: local and general.

Osteology

• Osteology is the scientific study of bones.

• Bones perform an important role by providing structure and protection to the body and its organs.

• Osteology has implications in the fields of medicine, surgery, paleontology, and evolutionary biology.

• The skeletal system of humans is comprised of 206 bones on average.### Human Bones

• Divided into 2 categories: appendicular bones (found in appendages like arms and legs) and axial bones (found along the central axis of the human body)

• Axial bones include bones in the skull and ribs and sternum

• The skull is comprised of 22 bones, including 8 neurocranial bones and 14 facial bones

• The thoracic cage, formed by the ribs and sternum, protects organs like the heart and lungs

• The sternum is divided into 3 segments: manubrium, body, and xiphoid process

Plant Classification

• Plants can be classified into 2 groups: vascular and nonvascular
• Vascular plants have xylem and phloem, while nonvascular plants do not
• Vascular plants can be further classified into gymnosperms (seeds but no flowers) and angiosperms (seeds and flowers)
• Angiosperms can be divided into monocots (1 seed leaf, flower petals in threes, parallel veined leaves) and dicots (2 seed leaves, flower petals in fours or fives, complex leaves with veins)

Leaf Structure

• Leaves are the primary site of photosynthesis in plants
• Leaf structure consists of several layers: cuticle, upper epidermis, palisade layer, spongy layer, and lower epidermis
• The palisade layer is where most photosynthesis takes place
• The spongy layer stores the products of photosynthesis and contains vascular bundles
• The lower epidermis secretes a waxy cuticle layer and has stomata that open and close to facilitate gas exchange and transpiration

Nitrogen Cycle

• Nitrogen is an essential element for life, used to make proteins, DNA, and chlorophyll
• Atmospheric nitrogen is not bioavailable, but some prokaryotes can fix nitrogen into bioavailable forms like ammonia
• Nitrogen-fixing prokaryotes can live in water or soil, or form symbiotic relationships with plants like legumes
• The nitrogen cycle describes the perpetual cycling of nitrogen between its gaseous form in the atmosphere and its bioavailable forms in the soil

Flowers and Pollination

• The study of plants is called botany, and the study of flowers is a specialty within it
• Flowers are the reproductive structures of angiosperms
• The structure of a flower includes four whorls: calyx, corolla, androecium, and gynoecium
• Pollination occurs when pollen is transferred from one flower to another by pollinators and other vectors
• Pollination can occur through self-pollination or cross-pollination, and is necessary for the reproduction and survival of plants
• Different plants have evolved strategies to support successful reproduction and different pollination methods

Skeletal Muscles

• Definition: Muscles with voluntary movement attached to bones through tendons
• Structure: Comprised of bundles of muscle fibers, each containing myofibrils made of actin and myosin proteins
• Functions: Movement, support, and homeostasis (regulation of body temperature)

Lever Systems

• Definition: Formed by muscles and bones to provide a mechanical advantage
• Components: Lever (bone), pivot/fulcrum (joint), effort (force generated by muscle contraction), and load (weight moved by the lever)
• Types: First-class (effort between pivot and load), second-class (load between effort and pivot), and third-class (pivot between effort and load)
• Examples: Atlanto-occipital joint (first-class), standing on tiptoes (second-class), bending elbow (third-class)

Basal Metabolic Rate (BMR)

• Definition: Minimum amount of calories required for basic functions at rest
• Different from RMR (resting metabolic rate)
• Equations: Harris-Benedict equation, Mifflin-St. Jeor equation
• Factors affecting BMR: Temperature, genetics, age, and gender

Connective Tissue

• Definition: Tissue that supports, protects, and gives structure to other tissues
• Types: Fibrous connective tissue (ligaments, tendons, fasciae), and others
• Functions: Supports, protects, and connects tissues and organs

Glutamine

• Definition: Non-essential amino acid produced by the human body and acquired through diet
• Functions: Important during pregnancy, lactation, neonatal growth, and recovery from trauma and chronic illness
• Structure: Polar, hydrophilic amino acid with a linear structure
• Sources: Eggs, legumes, and meat products

Digestion

• Definition: Breakdown and absorption of food in the body
• Mechanisms: Mechanical digestion (mixing food with saliva) and chemical digestion (enzymes break down food into molecules)
• Locations: Mouth, alimentary canal, and salivary glands
• Functions: Breaks down food into molecules, absorbs nutrients

Light Transmission

• Definition: Process by which light is transmitted to the brain
• Mechanisms: Photoreceptors (rods and cones) convert light into electrical signals, which are transmitted to the brain
• Functions: Enables vision, allows us to see and interpret light

Hearing

• Definition: Process by which sound vibrations are transmitted to the brain
• Mechanisms: Sound vibrations are collected by the ear, converted into electrical signals, and transmitted to the brain
• Functions: Enables hearing, allows us to interpret sound

Cornea

• Definition: Structure present on the anterior surface of the eye
• Layers: Epithelium, Bowman's layer, stroma, Dua's layer, Descemet's membrane, and endothelium
• Functions: Protects the eye, allows light to enter

Sound Sensitivity

• Definition: Increased sensitivity to sound
• Causes: Tiredness, stress, anxiety, head trauma, surgery, facial nerve damage, and conditions like Bell's palsy
• Effects: Increased perception of sound intensity

Virology

• Definition: Scientific study of viruses
• Structure: Collection of genetic coding with DNA or RNA surrounded by a protective protein coat
• Size: Range from 17 nanometers to 1.5 micrometers
• Functions: Reproduce and cause infection in host cells

Infections

• Definition: Invasion of the body by external pathogens
• Causes: Viruses, bacteria, parasites, and prions
• Effects: Illness, disease, and perturbations in bodily functions
• Types: Infectious and noninfectious diseases

Disordered Eating

• Definition: Pathological and unhealthy pattern of eating
• Symptoms: Recurrent binge eating, compensatory behavior, and self-evaluation influenced by body shape and weight
• Types: Bulimia nervosa, purging bulimia, and non-purging bulimia
• Treatments: Education, cognitive-behavioral therapy

Dyspnea

• Definition: Difficult or labored breathing
• Causes: Lung and heart disease, allergic reactions, and foreign body aspiration
• Treatments: Asthma inhalers, blood thinners, surgery, and oxygen

Anesthesia

• Definition: Medicine used to subdue a patient during medical procedures
• Types: Local, regional, and general anesthesia
• Stages: Stage 1 (loss of consciousness), stage 2 (REM stage), stage 3 (surgical procedure), and stage 4 (overdose)
• Side effects: Numbness, nausea, vomiting, and fatigue

Analgesia

• Definition: Relief or reduction of pain through the use of analgesics
• Types: NSAIDs, COX-2 inhibitors, and opioids
• Mechanisms: Inhibit the release of prostaglandins, block pain messages, and create a blockade in the central nervous system

Osteology

• Definition: Scientific study of bones

• Functions: Provide structure and protection to the body and its organs

• Importance: Implications in medicine, surgery, paleontology, and evolutionary biology### Human Bones

• Divided into 2 categories: appendicular bones (found in appendages like arms and legs) and axial bones (found along the central axis of the human body)

• Axial bones include bones in the skull and ribs and sternum

• The skull is comprised of 22 bones, including 8 neurocranial bones and 14 facial bones

• The thoracic cage, formed by the ribs and sternum, protects organs like the heart and lungs

• The sternum is divided into 3 segments: manubrium, body, and xiphoid process

Plant Classification

• Plants can be classified into 2 groups: vascular and nonvascular
• Vascular plants have xylem and phloem, while nonvascular plants do not
• Vascular plants can be further classified into gymnosperms (seeds but no flowers) and angiosperms (seeds and flowers)
• Angiosperms can be divided into monocots (1 seed leaf, flower petals in threes, parallel veined leaves) and dicots (2 seed leaves, flower petals in fours or fives, complex leaves with veins)

Leaf Structure

• Leaves are the primary site of photosynthesis in plants
• Leaf structure consists of several layers: cuticle, upper epidermis, palisade layer, spongy layer, and lower epidermis
• The palisade layer is where most photosynthesis takes place
• The spongy layer stores the products of photosynthesis and contains vascular bundles
• The lower epidermis secretes a waxy cuticle layer and has stomata that open and close to facilitate gas exchange and transpiration

Nitrogen Cycle

• Nitrogen is an essential element for life, used to make proteins, DNA, and chlorophyll
• Atmospheric nitrogen is not bioavailable, but some prokaryotes can fix nitrogen into bioavailable forms like ammonia
• Nitrogen-fixing prokaryotes can live in water or soil, or form symbiotic relationships with plants like legumes
• The nitrogen cycle describes the perpetual cycling of nitrogen between its gaseous form in the atmosphere and its bioavailable forms in the soil

Flowers and Pollination

• The study of plants is called botany, and the study of flowers is a specialty within it
• Flowers are the reproductive structures of angiosperms
• The structure of a flower includes four whorls: calyx, corolla, androecium, and gynoecium
• Pollination occurs when pollen is transferred from one flower to another by pollinators and other vectors
• Pollination can occur through self-pollination or cross-pollination, and is necessary for the reproduction and survival of plants
• Different plants have evolved strategies to support successful reproduction and different pollination methods