Anatomy and Physiology: Organ Systems

• The upcoming exam 3 will test on how form relates to function.
• A description of major organ systems and how they interact will also be tested.
• Organ systems include digestion, osmoregulation, circulation, respiratory, immune, reproductive, and nervous systems.

Relationship Between Anatomy and Physiology

• Animal form (anatomy) and function (physiology) are related throughout all levels of organization.
• Environmental pressures have selected for particular body features that increase survival and reproduction.
• Restrictions on animal body plans and sizes are caused by the animals requirement to exchange materials.
• Homeostasis in animals is the maintenance of a relatively constant internal environment regulated by feedback loops.
• Four main types of animal tissues are epithelial, connective, muscle, and nervous.
• Animal form, also known as anatomy, features of the animal's phenotype.
• Animal function, also known as physiology, is how animals use their phenotype to do specific tasks.
• Natural selection favors adaptations to environment.
• Conversant evolution represents similar body forms resulting from similar environmental pressures.

Constraints on Form and Function

• Cells have to exchange nutrients and wastes across cell membrane.
• Exchange rate is proportional to the surface area of the cell.
• The amount of nutrients required and wastes generated is proportional to cell volume
• Surface area to volume ratio limits cell size.
• To get bigger organisms must become multicellular.

Benefits of Being Large

• Organ systems and bulk transport move nutrients and wastes to and from internal cells.
• Local exchange occurs across cell membranes.
• Interstitial fluid is the environment between cells and transport systems.
• Larger body sizes need larger skeltons and more muscles.
• Creating a 6000 kg chicken is not possible.

Tissue Types

• Cells create tissues, that create organs, that create organ systems which create an organism.
• The four major types of animal tissues are epithelial, connective, muscle, and nervous.
• The following make up 4 main types of tissues

Epithelial Tissue

• Epithelial tissue creates the outside body and lines cavities and organs
• The basal surface is attached to basal lamina and the top underlying tissue.
• The apical surface is the side of a cell that looks at the outside lumen (cavity) or outside the organ.
• Epithelial tissue has a Barrier to injury, pathogens, fluid loss
• Epithelial tissue has a use in secretion and absorption
• Simple columnar epithelium lines intestines, is often involved in secretion and also involved in absorption.
• Stratified squamous epithelium makes up skin and other tissues that are constantly replaced.
• Cuboidal epithelium creates kidney tubules and various specialized glands for secretion
• Pseudostratified columnar epithelium lines respiratory tract, secretes mucous (dissolve gases) and cilia create mucous flow

Connective Tissue

• Connective tissue binds & supports other tissues and cells in extracellular matrix.
• Connective tissue has protein fibers in extracellular matrix
• Collagenous fibers provide strength and flexibility making it difficult to tear
• Reticular fibers are continuous with collagenous fibers and join connective tissue to other tissues.
• Elastic fibers provide stretch and recoil.
• Loose connective tissue binds and anchors epithelia to underlying tissues.
• Fibrous connective tissue is comprised of dense collagenous fibers forming bundles
• Tendons attach muscles to bones.
• Ligaments connect bones at joints.
• Cartilage is strong and flexible and it makes up skeletons of many vertebrate embryos.
• Chondrocytes cells secrete collagenous fibers and matrix.
• Bone is made of mineralized connective tissue.
• Osteoblast deposit collagen matrix filled with mineral ions.
• Osteons create concentric layers around a central canal containing blood vessels and nerves.
• Adipose tissue is a specialized loose connective tissue for storing fat (fuel) which can pad and insulate the body.
• Blood transports through the body using plasma = liquid extracellular matrix.
• Plasma contains: water, salts, dissolved proteins, erythrocytes (carry O2 & CO2), leukocytes (immune response), & platelets (cell fragments for clotting).

Muscle Tissue

• There are 3 major types of muscle, smooth, skeletal, and cardiac.
• Smooth muscle can be located in the walls of blood vessels and visceral organs
• Smooth muscle has no striations, is not branched, is not voluntary, and is slow.
• Skeletal muscle is in locations that attach to skeletal elements and has striated muscle tissue.
• Skeletal muscle is not branched, voluntary, and fast.
• Cardiac muscle is located only in the heart, is striated and branched.
• Control of cardiac muscle is involunatry, and is fast.

Nervous Tissue

• Nervous tissue transmits information using neurons, and neuronal cells, which receive signals through dendrites.
• Neurons process information in the cell body, and sends signals using axons
• Glial cells provide support to neurons and insulate synapses while nourishing neurons
• The brain is a concentration of nervous tissue
• Nervous tissue sends and receives signals.
• The statement "The effects of nervous systems can be long lasting" is false.

Nervous System and Endocrine Systems:

• The nervous system is characterized by a specific pathway: neuron, muscle, endocrine cells
• The nervous system is related to immediate and rapid response.
• The endocrine system sends hormones.
• The endocrine system has receptors in specific cells and tissues.
• The endocrine system creates gradual changes with long-lasting effects.
• Two systems, nervous and endocrine, works in close coordination to maintain a stable internal environment

Homeostasis

• Homeostasis involves Conformers allow body to match environment and regulators set their body state and keep it constant.
• Homeostasis maintains a relatively constant internal environment by balancing temperature, pH, blood sugar, hormone levels
• Set points and ormal ranges can change with age or show cyclic variation, like menstrual, circadian, or circannual cycles.
• Circadian rhythms have a direct effect on amount of melatonin released.
• Physiological night impacts hormone release.
• Energy-mobilizing hormones released primarily in the morning, and body temperature tends to be higher in day than at night.
• Homeostasis is controlled by negative feedback loops and the response is that brings variable back to homeostatic set point.
• Body temperature is regulated by the hypothalamus
• The correct sequence of bodily responses to increased temperature is:
  • Body temperature increases.
  • Thermostat in hypothalamus activates cooling mechanisms.
  • Sweat glands secrete sweat, and blood vessels in skin dilate.
  • Body temperature decreases.
• Acclimatization is adjustment to external environment but not the adaptation
• Spending time at high altitude increases red blood cell count, increases respiration, and acidification of blood to counter alkalinity from increased respiration.