DOC PREVIEW
BU BIOL 118 - BIO118 42lec

This preview shows page 1 out of 2 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 2 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Chpts 42 Lecture Notes- In biology, structure has a profound influence on function. Biologists analyze the structure and function of animals at avariety of levels: molecules, cells, tissues, organs, and organ systems.- Body size has a strong influence on how animals work, in large part because a body’s volume increases faster than its surface area as body size increases.- Animals use an array of methods to maintain a relatively constant environment inside their bodies = homeostasis. They have systems that sense changes in internal conditions and trigger responses that return conditions to normal.- Some animals have sophisticated systems for generating and conserving heat and regulating body temperature.Anatomy is the study of an organism’s physical structurePhysiology is the study of how the physical structures in an organism functionTissues, Organs, and SystemsIf a structure found in an animal is adaptiveThe structure’s size, shape, or composition will correlate with its functionIf a mutant allele alters the size and shape of a structure to make function more efficient, individuals with that allele produce more offspring. Allele will increase in frequency over time.Correlations between form and function begin at the molecular level. For example, protein shape correlates with their role as enzymes, structural components of the cell, or transporters. Similar function between structure and function occur at the cellular level. For example, cells that secrete digestive enzymes contain a lot of rough ER and Golgi. Absorptive cells have a large surface area.A tissue is a group of similar cells that function as a unitAdult tissue types are: Connective, Nervous, Muscle, and EpithelialConnective TissueConsists of cells loosely arranged in a liquid, jellylike, or solid matrix secreted by the connective tissue cells themselves.The nature of the matrix determines the nature of the connective tissue. Types of connective tissue:-Loose connective tissue—contains an array of fibrous proteins in a soft matrix (ie. reticular tissue and adipose tissue)-Dense connective tissue—found in the tendons and ligaments; connects muscles, bones, and organs-Supporting connective tissue—has a firm extracellular matrix (ie. bone and cartilage)-Fluid connective tissue—cells surrounded by a liquid extracellular matrix (ie. blood)Nervous tissue consists of nerve cells, or neurons, and several types of supporting cellsMost neurons have two distinct types of projections from the cell body, where the nucleus is locatedShort, branching dendrites, which transmit electrical signals from other cells to the cell bodyLong axons, which carry electrical signals from the cell body to other cellsMuscle tissue was a key innovation in the evolution of animals—like nervous tissue, it appears in no other lineage. Muscle tissue functions in movement.There are three types of muscle tissue:1. Skeletal muscle2. Cardiac muscle3. Smooth muscleEpithelial Tissue (epithelia) are tissues that cover the outside of the body, line the surfaces of organs, and form glandsAn organ is a structure that serves a specialized function and consists of several tissues. A gland is a group of cells that secrete specific molecules or solutions.Epithelia carry out several functions:-Protection-Transport of water and nutrientsEpithelial cells typically form layers of closely packed cellsAll epithelial tissue have polarity. The apical side faces away from other tissues. The basolateral side faces the animal’s interior.The basal lamina connects the epithelial to the connective tissue. The apical and basolateral sides of an epithelium have distinct structures and functions:- apical side of an epithelium generally lines organs and secretes mucus (ie. lining of the esophagus)- basolateral side cements the apical to the basal laminaSurface Area/Volume Relationships: TheoryThe cell surface area determines the rate at which gases and nutrients diffuse across the membrane. The cell volume determines the rate of diffusion. As a cell gets larger, its volume increases much faster than its surface area does. The area/volume affect the animal’s overall physiology. The physiological activity can be measured as the metabolic rate.http://www.youtube.com/watch?v=xuG4ZZ1GbzISurface Area/Volume Relationships: DataMetabolic rate is the overall rate of energy consumption. Consumption of energy is measured as the basal metabolic rate. The BMR is the rate at which an animal consumes oxygen while at rest with an empty stomach, under normal temperature and moisture conditions (measured in mL of O2 consumed per gram of body mass per hour)1On a per-gram basis, small animals have higher BMRs than do large animals. As an organism’s size increases, its mass-specific metabolic rate must decrease or the surface area available for exchange of materials would fail to keep up with the metabolic demands of the organism.Adaptations That Increase Surface AreaIncreases in surface area relative to its volume are achieved in three ways:1. Flattening (ie. fish gills have flattened, sheetlike structures called lamellae1. Folding (ie. mammal small intestine has folds called villi)1. Branching (ie. small blood vessels called capillaries are highly branched)Homeostasis is the maintenance of relatively constant internal environmentInternal chemical and physical states are kept within a tolerable rangeConstancy of physiological state can be achieved by conformation and/or regulation.Each variable has a set point―a normal or target valueA homeostatic system is based on three general components:A sensor is a structure that senses some aspect of the external or internal environmentAn integrator is a component of the nervous system that evaluates the incoming sensory information and “decides” if a response is necessary to achieve homeostasisAn effector is any structure that helps restore the desired internal conditionHomeostatic systems are based on negative feedback, in which effectors reduce or oppose the change in internal conditions(ie. changes in blood pH; blood pressure)How Do Animals Regulate Body Temperature?Overheating can cause proteins to denature. Protein denature can lead to dehydration. Low body temperatures can slow down enzyme function and energy production.Mechanisms of Heat ExchangeAll animals exchange heat with their environment in four ways:1. Conduction2. Convection3. Radiation4. EvaporationMany animals can control their body temperature through the


View Full Document

BU BIOL 118 - BIO118 42lec

Download BIO118 42lec
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view BIO118 42lec and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view BIO118 42lec 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?