Human Anatomy and Tissue Quiz

Animal Body Systems Organization

• Animal bodies organized into cells, tissues, organs, and organ systems
• Cells specialize and combine in different ways to form tissues, organs, and organ systems
• Specialization allows multicellular organisms to maintain a stable internal environment independent of external changes

Organ Systems

• Eleven major organ systems in vertebrates
  • Respiratory system (lungs, diaphragm, trachea): gas exchange with environment
  • Digestive system (oral cavity, esophagus, stomach, intestines): converts ingested matter to absorbable molecules, eliminates undigested matter
  • Reproductive system (ovaries, uterus, testes): maintains sexual characteristics and passes genes to next generation
  • Excretory system (kidneys, bladder): removes and eliminates excess water, ions, and metabolic wastes
  • Nervous system (brain, spinal cord, peripheral nerves): principal regulatory system, coordinates body activities
  • Endocrine system (pituitary, hypothalamus, thyroid, adrenal, pancreas): regulates body activities through hormone secretion
  • Muscular system (skeletal, cardiac, smooth muscles): moves body parts, helps bodily functions, generates heat
  • Skeletal system (bones, tendons, ligaments, cartilage): supports and protects body parts, provides leverage for movement, stores minerals
  • Integumentary system (skin, sweat glands, hair, nails): covers external body surfaces, protects against injury and infection, regulates water and body temperature
  • Circulatory system (heart, blood vessels, blood): distributes water, nutrients, oxygen, hormones, carries away metabolic wastes and helps maintain temperature and pH
  • Immune system (lymph nodes, thymus, bone marrow): defends against disease-causing microorganisms and viruses.

Tissue Types

• Epithelial tissue: sheets of cells that cover surfaces, line cavities & ducts (e.g., skin, lining of the digestive tract)
• Connective tissue: diverse supporting tissues with an extracellular matrix, provides support, transmits forces (e.g., bone, cartilage, blood)
• Muscle tissue: contractile tissues that produce movement (e.g., skeletal, cardiac, smooth muscle)
• Nervous tissue: neurons that transmit electrical and chemical signals; glial cells that support neurons.

Glands

• Secretory structures derived from epithelia
• Exocrine glands: connected to an epithelium by a duct that empties on the epithelial surface
• Endocrine glands: ductless; no direct connection to an epithelium

Nervous Tissues

• Neurons: communicate information between body parts via electrical and chemical signals
• Glial cells: support and provide nutrients to neurons, provide electrical insulation between them, scavenge cellular debris and foreign matter

Neuron Structure

• Dendrites and cell body: receive and integrate signals toward the spike initiation zone
• Axons: transmit signals away from the spike initiation zone to other neurons or effectors

Neuron Types

• Afferent neurons (sensory): conduct information from sensory receptors
• Interneurons: integrate information into a response
• Efferent neurons (motor): carry response signals to effectors

Neural Signals and Circuits

• Afferent, interneuron, and efferent neurons form a basic circuit
• Circuits combine into networks that interconnect the peripheral and central nervous systems

Animal Nervous Systems

• Functions of nervous systems result from neuron and glial cell activities
• Nervous systems organize into complex networks in most animals
• Peripheral nervous system (PNS) projects of neurons (axons) are bundled into cable-like projections (nerves)
• Nerves provide a pathway between different structures and the central nervous system (CNS)
• In the CNS, networks are organized into ganglia and brains

Four Functions of the Nervous System

• Reception: detection of a stimulus
• Integration: integrates information to formulate an appropriate response
• Transmission: conducts message along neurons
• Response: transmits a signal to effector organs to produce a response

Glial Cells

• Astrocytes: help maintain ion balance surrounding neurons
• Oligodendrocytes/Schwann cells: form insulating layers around axons (myelin)

Next Week

• Membrane potentials
• Action potentials
• Synaptic transmission
• Post-synaptic electrophysiology
• Nervous system evolution
• Functional divisions of the vertebrate nervous system