BIOSCI 107 Lecture Notes

BIOSCI 107 Lecture 1 Notes - Body Systems Biology for Biomedical Science

Overview of Cells and Tissues

  • Cells: Noteworthy Features

    • Size

    • Shape

    • Characteristic features

  • Basic Types of Tissue (4 Types):

    1. Epithelial

    2. Muscle

    3. Connective

    4. Nervous

Body Systems

  • Composed of related organs working together to perform common functions.

Integumentary System

  • Components:

    • Skin Structure:

    1. Epidermis

    2. Dermis

    3. Hypodermis

Epidermis

  • Type: Stratified squamous epithelium

  • Features:

    • Multiple layers of thin, tile-like epithelial cells

  • Functions:

    • Protects the surface and deeper tissues

    • Produces vitamin D

Dermis

  • Composition:

    • Mainly connective tissue, divided into two layers:

    1. Papillary layer

    2. Reticular layer

  • Functions:

    • Feeds the epidermis with blood vessels/nutrients for nourishment

    • Provides strength and support

    • Contains glands for:

    • Hair follicles and sebaceous glands (protection, lubrication, sensation)

    • Sweat glands (thermoregulation, evaporative cooling)

    • Nails grow from the dermis, emerging through the epidermis

    • Houses sensory receptors (detect sensations: touch, pressure, temperature, pain)

Hypodermis

  • Function:

    • Contains fat storage

    • Acts as a bridge between the skin and deeper layers

Muscular System (Skeletal)

  • Primary Functions:

    • Engages in skeletal movement

    • Controls entrances/exits of substances in digestive, respiratory and urinary systems

    • Produces heat (via shivering)

    • Provides support for the skeleton

    • Protects soft tissue

Muscle Categorization

  • Types:

    1. Axial Muscles: Core muscles for support and positioning of the axial skeleton

    2. Appendicular Muscles: Support and movement of limbs

Connective Structures

  • Tendons:

    • Inflexible, fibrous, rope-like connections between muscle and bone

  • Aponeuroses:

    • Sheet-like connections, often muscle-muscle

  • Function of Tendons and Aponeuroses:

    • Translate contractile forces into tasks (muscles pull on tendons/aponeuroses to move bones)

Skeletal System

  • Components:

    • Bones, joints, cartilage, ligaments

Cartilage

  • Type: Strong, flexible connective tissue

  • Functions:

    • Protects bones and joints

    • Prevents duplication against adjacently positioned bones

  • Composition:

    • Dependent on function and associated bones

Axial Skeleton

  • Components:

    • Skull, vertebrae, sacrum, coccyx, sternum, supporting cartilages, ligaments

  • Functions:

    • Protects brain, spinal cord, sense organs, soft tissues of thorax

    • Supports body weight over lower limbs

Bone

  • Storage:

    • Minerals

    • Two types of bone marrow: red and yellow

    • Body regulates production of both types based on needs

  • Example:

    • After major bleeding, yellow marrow can convert to red to restore RBC levels

Central Nervous System (CNS)

  • Function:

    • Directs immediate responses to stimuli by coordinating activities of other organ systems.

Appendicular Skeleton

  • Components:

    • Limb bones, supporting cartilages, ligaments

  • Functions:

    • Provides internal support for external limbs

    • Allows muscles to move the axial skeleton

  • Bone Marrow Types:

    • Red: Produces red blood cells; dominant at birth

    • Yellow: Storage of fat cells; increases with age

Nervous System

  • Brain Functions:

    • Performs complex integrative activities (voluntary and involuntary actions)

  • Spinal Cord Functions:

    • Interchanges information between brain and peripheral nerves

    • Performs less complex integrative activities

  • Peripheral Nervous System (PNS):

    • Links CNS to other systems and sense organs

    • Special Senses:

    • Detects and relays sensory input related to sight, hearing, smell, taste, equilibrium

Endocrine System

  • Description:

    • A network of hormone-producing glands regulating bodily functions

  • Key Glands and Their Functions:

    • Pineal Gland: Regulates melatonin production for day-night rhythms

    • Hypothalamus/Pituitary Gland: Controls other endocrine glands, regulates growth and fluid balance; biological clock location

    • Thyroid Gland: Controls metabolic rate via thyroxine secretion

    • Parathyroid Gland: Controls calcium levels

    • Thymus: Supports lymphocyte maturation

    • Adrenal Glands: Control water-mineral balance

    • Kidneys: Produce red blood cells, maintain blood pressure, regulate calcium levels

    • Pancreas: Regulates glucose levels

    • Gonads: Control sexual characteristics and reproduction

Growth Hormone Disorders

  • Gigantism:

    • Caused by excessive growth hormones (GH) during childhood

  • Acromegaly:

    • Resulting from excessive GH in adulthood

    • Causes thicker tissues without increased height (growth plates closed)

  • Goitre:

    • Result of oversized thyroid gland

Lymphatic System

  • Function:

    • Returns excess fluids from tissues to circulatory system

Components:

  • Lymphatic Vessels:

    • Contractile; carry lymph fluid and lymphocytes to veins of the cardiovascular system

  • Lymphatic Fluids:

    • Compose of lipids and other fluids from tissues

  • Lymphocytes (B cells and T cells):

    • B cells: Attack foreign substances, viruses, bacteria

    • T cells: Destroy infected body cells

Lymph Nodes and Spleen

  • Lymph Nodes:

    • Stimulate immune response; expand to release macrophages to engulf pathogens

  • Spleen:

    • Monitors blood cell circulation, recycles RBC, produces immune responses

Cardiovascular System

  • Functions:

    • Pumps oxygenated blood throughout the body for nutrient transport

    • Maintains blood pressure

  • Component Functions:

    • Arteries: Carry oxygenated blood; thick to withstand high pressure

    • Capillaries: Facilitate diffusion of oxygen, carbon dioxide, nutrients

    • Veins: Return deoxygenated blood to the heart

  • Blood Functions:

    • Transports oxygen, carbon dioxide, nutrients, hormones, waste

    • Regulates temperature, immune responses, acid-base balance

Respiratory System

  • Functions:

    • Filter, warm, humidify air, detect smells

Components:

  1. Nasal Cavity/Paranasal Sinuses

  2. Pharynx: Conducts air to larynx

  3. Larynx: Protects trachea, holds vocal cords

  4. Trachea: Conducts air, supported by cartilage

  5. Bronchi/Bronchioles: Conduct air to lungs

  6. Lungs: Site of gas exchange (O2 and CO2) and acid-base balance

  7. Diaphragm: Contracts and expands for airflow

Digestive System

  • Functions:

    • Breaks down food physically and chemically for safe passage through digestive tract

Components:

  1. Oral Cavity:

  2. Mechanical and chemical breakdown using saliva

  3. Pharynx: Conducts food/liquids to esophagus

  4. Esophagus: Delivers food to stomach with muscular contractions

  5. Stomach: Chemical digestion in an acidic environment

  6. Small Intestine: Contains enzymes for nutrient absorption

  7. Liver: Produces bile to break down fats, regulates blood nutrients

  8. Gallbladder: Stores and concentrates bile

  9. Pancreas: Secretes digestive enzymes

  10. Large Intestine/Anus: Water and waste removal/storage

Urinary System

  • Functions:

    • Filters waste, water, salts from blood, forming urine

    • Regulates pH, ion concentration, blood volume, blood pressure

Components:

  • Kidneys: Filter blood, form urine

  • Ureters: Conduct urine to bladder via muscular contractions

  • Bladder: Stores urine prior to elimination via urethra

  • Erythropoietin (EPO):

    • Glycoprotein hormone produced by kidneys, promotes erythropoiesis, increases RBC production in response to activity

Reproductive System

Male

  • Components:

    • Testes produce sperm and hormones

    • Accessory organs: epididymis, ductus deferens, seminal glands, prostate gland, urethra

    • External genitalia: penis and scrotum

Female

  • Components:

    • Ovaries produce oocytes and hormones

    • Uterine tubes deliver oocytes and are main sites of fertilization

    • Uterus hosts embryonic development

    • External genitalia: vagina serves as both sperm entrance and birth canal

    • Mammary Glands: Provide nutrition for newborns (modified sweat gland from integumentary system)

Immune System

  • Primary Functions:

    • Protects the body from pathogens (viruses, bacteria, fungi, and parasites)

    • Identifies and removes abnormal cells, such as cancerous cells

    • Facilitates tissue repair after injury

  • Major Divisions:

    • Innate Immunity (Non-specific):

      • The first and second lines of defense that respond immediately to any foreign invader

      • Includes physical barriers (skin) and chemical barriers (stomach acid)

      • Involves inflammation, fever, and phagocytic cells like neutrophils and macrophages

    • Adaptive Immunity (Specific):

      • A refined response that targets specific pathogens

      • Develops biological "memory," providing faster responses upon subsequent exposure

      • Primarily involves lymphocytes (BB cells and TT cells)

  • Internal Defense Mechanisms:

    • Antigens: Unique markers on cells that the immune system uses to identify "self" vs "non-self"

    • Antibody-Mediated Immunity: BB cells produce antibodies to neutralize pathogens in body fluids

    • Cell-Mediated Immunity: Cytotoxic TT cells directly attack and destroy infected or abnormal host cells