32: Homeostsis ad Orginization of Animal Body

Homeostasis

ability to maintain the internal environment, in a narrow limit for optimal function

first described by homeostasis

claude bernard (19th century)

coined homeostasis

walter cannon 1920's

conditions regulated by homeostasis

-temp

-ph

-water and salt concentration

-cluclose, gas ( co, co2)

Homeostasis requires

adjustment, it is not static

Enzymes rely on

3d struturce held by hydrogen bonds

slows/ stops reaction

change in salt pH and temp

Temp sensitivity

low temp: slows motion and interaction

high temp: reaction too fast, denatures proteins

Ectotherms

-get heat from enviornment

- reptiles, amphibians,fish, invertibratses

- have behaviors to stablizie temp

Endotherms

heat from metabolic reactions

Endotherms have higher

energy cost but faster nerveous system

Negetive Feedback

-primary mechanism

-counteracts change and returns the system to origional

- componetes: sensor, control center, effectir

sensor

detects condition

control center

compars condition to setpoint

effector

produces output to restore the condition

Shivering

response to cold; body shakes to turn energy from food into body heat

sweating

Getting rid of excess heat through pores in the skin to stay cool.

positive feedback

-resposne that amplifies change

-rare because it can spiral out of control

childbirth

cervix stretches triggers oxytocin, creates more contractions, contniues stretching

Structural Hierarchy

Cells, tissue, organs, organ system

Tissue

groups of cells for a similar task

organs

structure of 2+ tissues

organ system

groups of organs working together

Epithetical Tissue

-covers body surfaces and cavaties and glands

-high retention rate , non-vascular, attached to membranes

-classification: layer, shape

-Glands: Exocrine and Endocrine

layer classification

simple: one layer (diffusion or absorption)

stratified: multiple layers (protection)

shape classification

Squamous (flattened), cuboidal (cube-shaped), and columnar (column-shaped) cells.

Exocrine gland

secrets into ducts (sweat and saliva)

Endocrine gland

Ductless, secrets horomones into blood

Connective tissue

-supports and strength to other tissue

-large extracellular matrix

-connective: loose, dense and specialized

loose connective

most abundant

adipose: muscle to bone

ligaments: bone to bone

dense connective

-colllagen packe

- tendons: muscle to bone

-ligaments: bone tob bone

specialized connective

cartilage: flexable supprt

Bone: hardend by calcium

Blood and Lymph: Fluid matrices (plasma) carrying cells

Muscle Tissue

-cells packed with fibourus protein

- slide for contraition

-skeletal, cardiac, smooth

skeletal muscle

strained, voluntary, moves the skeleton

cardiac muscle

invoulitary, strained, heart cells, connected by interlaced disks

smooth muscle

no strained, invoulantary,digestive tract,

Nerve Tissue

-electrecal signaling

-Neurons

-Glial Cells

Neurons

conduct signaling through dendrites(input) cell and body axons (output)

Glial Cells

support, protect, and insulate neurons

Representive Organs:skin

-represent all 4 tissues working together to maintain homeostasis

-epithelial: epidermeis with water proof barier

-connective: dermis gives strength and contains blood vessels

- muscle: tiny muscles attaches to hair follicils

- nerve: sensor ending detects touch pressure and temp