Lecture 11 BIO 311D 1st EditionOutline of Last Lecture I. Cell Structure and SpecializationII. Reproduction and DevelopmentIII. Body PlansIV. TissuesV. Protostome and Deuterostome DevelopmentsOutline of Current Lecture I. Evolution of Animal Size and ShapeII. Hierarchical Organization of Body PlansIII. Tissuesa. Epithelialb. Connectivec. Muscle d. Nervous Current LectureWhich statement is true?A. Cells organized into tissuesB. B. Tissues are organized into organsC. Organs are organized into organ systemsD. All of the above are trueE. None of the above are trueEvolution of Animal Size and Shape:• Physical laws constrain strength, diffusion, movement, and heat exchange• As animals increase in size, their skeletons must be proportionately larger to support their mass• Evolutionary convergence reflects different species’ adaptations to a similar environmental challenge• A single-celled protist living in water has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm• Multicellular organisms with a saclike body plan have body walls that are only two cells thick, facilitating diffusion of materials• Pressure changes, diffusion, and a very complex system that increases surface area to volume ratio helps multicellular organisms reach the desired nutrients essential for survival• In flat animals such as tapeworms, the distance between cells and the environment is minimized• More complex organisms have highly folded internal surfaces for exchanging materials• In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells• A complex body plan helps an animal living in a variable environment to maintain a relatively stable internal environment Hierarchical Organization of Body Plans:- Tissues: Specialized cells are organized into tissues that have different functionsWhat are the four types of tissues?A. Muscle, immune, endocrine, nervousB. Nervous, connective, epithelial, skeletalC. Connective, muscle, epithelial, nervousD. Epithelial, connective, muscle, immune- Tissues are classified into four main categories:o Epithelial Main function is for protection Covers the outside of the body and lines the organs and catities within the body Contains cells that are closely joined The shape of epithelial cells may be cuboidal (dice), columnar (bricks) or squamous (like floor tiles) Epithelial cells may be: - Single layered (simple)- Multiple tiers of cells (stratified)- A single layered of cells varying in length (pseudostratified)o Connective Mainly binds and supports other tissues Contains sparsely packed cells scattered throughout an extracellular matrix Matrix consists of fibers in a liquid, jellylike, or solid foundation There are three types of connective tissue fiber, all made of protein:- Collagenous fibers provide strength and flexibility- Elastic fibers stretch and snap back to their original length- Reticular fibers join connective tissue to adjacent tissues Connective tissue contains cells, including- Fibroblasts that secrete the protein of extracellular fibers- Macrophages that are involved in the immune system In vertebrates, the fibers and foundation combine to form six major types of connective tissue: - Loose connective tissue binds epithelia to underlying tissues and holds organs in place- Cartilage is a strong and flexible support material- Fibrous connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints Adipose tissue stores fat for insulation and fuel Blood is composed of blood cells and cell fragments in blood plasma Bone is mineralized and forms the skeletono Muscle Most abundant of all tissues Consists of long cells called muscle fibers which contract in response to nerve signals Can be voluntarily controlled or involuntary controlled It is divided in the vertebrate body into three types: - Skeletal muscle, or striated muscle, is responsible for voluntary movemento Striated and voluntarily controlled- Smooth muscle is responsible for involuntary body activitieso Not striated and involuntarily controlled- Cardiac muscle is responsible for contraction of the hearto Striated and not voluntarily controlledo Nervous Nervous tissue senses stimuli and transmits signals throughout the animal Nervous tissue contains- Neurons, or nerve cells, that transmit nerve impulses- Glial cells, or glia, that help nourish, insulate, and replenish neurons- Organs: made of tissues (some organs belong to more than one organ system)- Organ system: made of organsHormones are:A. Fast acting with long lasting effectsB. Relatively slow acting but can have long lasting effectsC. Fast acting with effects that are quickly diminishedD. Relatively slow acting with effects that are quickly diminishedCoordination and Control:- Only some cells can receive hormones because only some organs have receptors for hormones- Hormones are sent through the blood stream- Control and coordination within a body depend on the endocrine system and the nervous system- The endocrine system transmits chemical signals called hormones to receptive cells throughout the body via blood- A hormone may affect one or more regions throughout the body- Hormones are relatively slow acting, but can have long-lasting effects- The nervous system transmits information between specific locations- The information conveyed depends on a signal’s pathway, not the type of signal- Nerve signal transmission is very fast- Nerve impulses can be received by neurons, muscle cells, endocrine cells, and exocrine cells- Animals manage their internal environment by regulating or conforming to the external environment- A regulator uses internal control mechanisms to moderate internal change in the face of external, environmental fluctuation- A conformer allows its internal condition to vary with certain external changes- Animals may regulate some environmental variables while conforming to othersHomeostasis:• Organisms use homeostasis to maintain a “steady state” or internal balance regardless of external environment• In humans, body temperature, blood pH, and glucose concentration are each maintainedat a constant level• Mechanisms of homeostasis moderate changes in the internal environment• For a given variable,