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Mammalian PhysiologyMammalian Physiology
You & me baby, we aint nothin’ but You & me baby, we aint nothin’ but mammals……mammals……
Animal CharacteristicsAnimal Characteristics• Multicellular,
heterotrophic eukaryotes
• No cell walls• Nervous & muscle
tissue present in most• Sexual reproduction,
diploid life cycle is dominant
• All have similar developmental stages
•
mammalsmammals
• Characteristics– Mammary glands
(milk)– Hair– Endothermic– Well developed
respiratory & circulatory systems
– Internal fertilization
MammalsMammalsmajor groupsmajor groups
• Monotremes– Egg layers
• Marsupials– Born early, complete
development while nursing
• Eutherians (placental)– Placenta, complete
internal development
Some vocab…Some vocab…
• Anatomy-structure• Physiology-function• Tissue-group of cells w/ common structure
& function– Most organs are made of several types of
tissues– Four categories:
1. Epithelial
2. Connective
3. Nervous
4. muscle
Homeostasis-maintained by self-regulating control Homeostasis-maintained by self-regulating control systems known as feedback mechanismssystems known as feedback mechanisms
• Negative feedback– Returns set point to normal,
or towards normal state– Response is opposite to that
of stimulus– Ex: body temp., blood
pressure, blood glucose– Most feedback mechanisms
in the body are negative
• Positive feedback– Moves away from normal
state– Response is in same
direction as that of stimulus, increases the change
– Ex: blood clotting, child birth– Positive feedback produces
instability in the body, and these reactions usually are short-lived
All feedback mechanisms involve three components:
1. Receptor-detects change2. Control center –processes info3. Effector-directs appropriate response to change
BioenergeticsBioenergetics• Metabolic rate-amount of energy an animal uses
in a given period of time– Calories or kilocalories– Inversely related to body size– NOT total calories consumed
• Ectotherms-fish, amphibians, reptiles– Do not maintain stable internal temp, it changes w/
surrounding– Measured as standard metabolic rte (SMR)-uses
specific temperature
• Endotherms-birds & mammals– Stable internal temp maintained by high metabolism– Measured as basal metabolic rate(BMR)-rest,
nonstressed, empty stomach
Epithelial TissueEpithelial Tissue• Tightly packed sheets
– Tight junctions important– “free” surface, & attached surface, known as basement membrane
• Cover outside of body, line organs & cavities within body• Functions
– Mechanical & biological barriers, prevent fluid loss• Classified by
– Number of layers• Simple• Stratified• Pseudostratified
– Shape• Squamous• Cuboidal• Columnar
– Ciliated (or not)– Glandular (or not)
• Mucous membranes
Connective TissuesConnective Tissues
General characteristics • most abundant tissue type• many functions
• bind structures• provide support and protection• serve as frameworks• fill spaces• store fat• produce blood cells• protect against infections• help repair tissue damage
• fewer cells, separated by a matrix(secreted by cells)• have cells that usually divide
5-11
Connective Tissue FibersConnective Tissue Fibers
Collagenous fibers• thick, nonelastic• composed of collagen protein• great tensile strength •hold structures together• tendons, ligaments
Elastic fibers• made of elastin protein•branched• elastic• vocal cords, air passages
Reticular fibers• very thin collagenous fibers• highly branched• form supportive networks 5-13
Connective Tissue Connective Tissue Major Cell TypesMajor Cell Types
Fibroblasts• fixed cell• most common cell • large, star-shaped• produce fibers
Macrophages• wandering cell• phagocytic• important in defense
5-12
Osteoblasts & osteocytes•Found in bone
Chondrocytes•cartilage
Various blood cells
Types of connective TissueTypes of connective Tissue
• Loose• Adipose• Fibrous• Cartilage• Bone• Blood
Adipose TissueAdipose Tissue
• cells called adipocytes• forms beneath the skin, around organs• fat pushes nuclei & other organelles to one side• Functions:
- insulates and protects
- reserve energy supply– cushions
Loose (Areolar) TissueLoose (Areolar) Tissue• most widely distributed throughout body• soft, pliable, with semi-fluid matrix• composed of fibroblasts, macrophages, and adipocytes• Widely distributed• Functions:
- wraps & cushions organs, binds to other tissue
Fibrous Connective TissueFibrous Connective Tissue• fibroblasts in rows between bundles of parallel collagen fibers• great strength• forms tendons & ligaments • Avascular• Dense regular, dense irregular• Function:
- provides strong attachments between structures, resists tensile stress in one direction
Hyaline CartilageHyaline Cartilage
• firm matrix made of collagen• found on ends of long bones, nose, parts of larynx, trachea, bronchi,
bronchial tubes, and embryonic skeleton• Little flexibility• Functions:
- supports & reinforces, resists compressive stress, cushioning
BoneBone
• Hard, calcified matrix (hydroxyapetite)• consists of osteons (haversion systems)
– contain lamellae(concentric circles), with lacunae containing osteocytes
– Lamellae around central canal(blood vessel)– Lacunae (osteocytes) connected by canaliculi
• Functions– Support & protection, – levers for muscles, – stores calcium & fat, – site of hematopoiesis(bone marrow)
BloodBlood• contains red blood cells, white blood cells, and platelets in fluid
matrix(plasma)• plasma consists of water with dissolved nutrients, ions, hormones,
gasses, and plasma proteins• Functions
– Transport respiratory gases, nutrients, wastes, etc
Muscle TissueMuscle Tissue
General characteristics
• specialized to contract or shorten to produce movement
• three types• skeletal• smooth• cardiac
Skeletal Muscle (striated)Skeletal Muscle (striated)
• attaches to skeleton• Voluntary control• fibers contain alternating light and dark bands (striation)• multinucleated• fibers are cylindrical in shape, parallel (NOT branched)
Cardiac MuscleCardiac Muscle• found only in the heart• striated , involuntary• fibers are branched with usually only one nucleus• attached to each other through intercalated discs-help
conduct electrical impulses
Smooth MuscleSmooth Muscle
• found in walls of hollow organs- stomach, bladder, uterus, blood vessels
• fibers are tapered, one nucleus
• NO STRIATIONS• has ability to propel objects
through the organ via peristalsis - wave-like motion