Human Body Overview Notes

10.1 - Human Body Overview

  • Unit 10 - Human Body

Levels of Organization

  • Every organ is in at least one system.
  • One organ can be in more than one system.

Tissue Types

  • There are 4 main types of tissue:

    1. Epithelial
    2. Nervous
    3. Connective
    4. Muscle

  • Nervous tissue

    • Brain
    • Spinal cord
    • Nerves

  • Epithelial tissue

    • Lining of GI tract organs and other hollow organs
    • Skin surface (epidermis)

  • Muscle tissue

    • Cardiac muscle
    • Smooth muscle
    • Skeletal muscle

  • Connective tissue

    • Fat and other soft padding tissue
    • Bone
    • Tendon

Epithelial Tissue

  • Lines surfaces, protects (dehydration, damage, etc.)
  • Few cells thick, tightly packed.
  • Lots of nerves, high repair/regeneration speed

Nervous Tissue

  • Communication, coordination.
  • Nerves + supporting cells.
  • Nerves = sensory & motor.
  • Examples: Brain, spinal cord, peripheral nerves.

Connective Tissue

  • Support, protect, transport, insulate.
  • Composed of cells + extracellular matrix (ground substance and fibers).
  • Types of Connective Tissue:
    • Loose connective tissue (under the skin)
    • Fibrous connective tissue (forming a tendon)
    • Adipose tissue
    • Cartilage (at the end of a bone)
    • Bone
    • Blood

Types of Connective Tissue

  • Blood
    • Liquid.
    • Fluid matrix (plasma) containing RBCs, WBCs, platelets.
  • Fibrous CT
    • In muscles, bone, skin.
    • Functions for support & shock absorption.
  • Adipose tissue
    • Insulation, energy storage, protective cushion.
  • Cartilage
    • Padding, shock absorption.
    • Examples: nose, respiratory passages, ear, between vertebrae, etc.

Muscle Tissue

  • Enables movement.
  • Three types:
    1. Skeletal
    2. Smooth
    3. Cardiac
Muscle Tissue TypeControl
Skeletal MuscleVoluntary
Smooth MuscleInvoluntary
Cardiac MuscleInvoluntary

3 Types of Muscle Tissue

  • Skeletal muscle
    • Striations
    • Nuclei
    • Connective tissue
  • Cardiac muscle
    • Striations
    • Intercalated disc
    • Branching
    • Nucleus
  • Smooth muscle
    • Glycogen
    • Nuclei
    • Muscle cells

Human Body Systems

  • There are 11 main systems that keep our bodies functioning.
  • The systems and their primary roles:
    • Endocrine: Regulation of body processes through hormone production.
    • Nervous: Processing center for sensory input, using the input to elicit appropriate responses.
    • Respiratory: Gas exchange between the internal and external environment.
    • Cardiovascular: Circulation of blood, which transports gases, nutrients, hormones, and wastes.
    • Digestive: Physical and chemical breakdown of food to allow absorption of nutrients.
    • Lymphatic: Circulation of lymph, which maintains fluid balance and helps fight infection.
    • Reproductive: Production of reproductive cells that will generate offspring.
    • Urinary: Filtration of blood and excretion of wastes from the body.
    • Integumentary: Protection against the external environment and regulation of temperature.
    • Skeletal: Support and protection of many internal organs.
    • Muscular: Voluntary and involuntary movement.

Body Cavities

  • Large fluid-filled spaces.
  • House & protect major internal organs.
    1. Dorsal Body Cavity
    2. Thoracic Cavity
    3. Abdominal Cavity
    4. Pelvic Cavity

Homeostasis

  • Involves regulation of:
    • Temperature
    • Metabolism
    • Water/nutrient levels
    • Response to stimuli
    • Etc!
  • Body temperature regulation as an example:
    • If body temperature falls:
      • Blood vessels constrict so that heat is conserved.
      • Sweat glands do not secrete fluid.
      • Shivering (involuntary contraction of muscles) generates heat, which warms the body.
      • Heat is retained.
    • If body temperature rises:
      • Blood vessels dilate, resulting in heat loss to the environment.
      • Sweat glands secrete fluid.
      • As the fluid evaporates, heat is lost from the body.
      • Heat is lost to the environment.

Positive Feedback Loop

  • Enhances original stimulus to push body further from homeostasis.
  • Examples: childbirth, blood clotting.
  • Childbirth example:
    • Head of baby pushes against cervix.
    • Nerve impulses from cervix transmitted to brain.
    • Brain stimulates pituitary gland to secrete oxytocin.
    • Oxytocin carried in bloodstream to uterus.
    • Oxytocin stimulates uterine contractions and pushes baby towards cervix.

Negative Feedback Loop

  • Reverses the original stimulus to return body to homeostasis.
  • Examples: breathing rate, blood glucose levels, body temperature, heart rate.