UTD Wilson Bio 2 exam 1 Fall 24'

what is anatomy?

the study of the structures of organisms

what is homeostasis?

the stable state of the internal environment

what creates an internal environment of multicellular organisms?

the fluid that supplies all the needs of individual cells including:

- nutrient supply

- waste removal

- osmotic balance

This allows for an occupation of a diverse external environment

multicellular organisms can become relatively large due to?

their individual cells being small enough to exchange materials with the internal environment

what are the requirements of individual animal cells?

- Must be surrounded by an aqueous solution containing ions and molecules in concentrations that maintain osmotic balance

- organic molecules as energy source

-oxygen for oxidative reactions

-removal of waste molecules and other by-products

-environmental conditions within tolerable limits

what are the levels of organization starting from cells?

cells

tissue

organ

organ system

organism

what is a tissue?

a group of cells with the same structure and function working together as a unit to carry out specialized activities

what is an organ?

integrates two or more different tissues into a structure that carries out a specific function

what is an organ system?

coordinates the activities of two or more organs to carry out a major body function

what is the structure and function of a tissue determined by?

- properties of the individual cells that make up the tissue

- structure and organization of the cytoskeleton

- type and organization of the extracellular matrix surrounding the cell

- the junctions holding cells together

what are the three types of cell junctions?

- anchoring junctions

- tight junctions

- gap junctions

what is an anchoring junction?

form buttonlike spots or belts that weld cells together- mostly found in tissues subject to stretching

what are tight junctions?

seal spaces between cells which keeps molecules and ions from leaking between cells

what are gap junctions?

open channels between cells in the same tissue allowing ions and small molecules to flow freely from one cell to another

what are the 4 basic tissue types?

epithelial

connective

muscle

nervous

what is the primary function of epithelial tissue?

protection, secretion, absorption

what is the primary function of connective tissue?

structural support

what is the primary function of muscle tissue?

movement

what is the primary functions of nervous tissue?

communication, coordination, control

what is the largest group of tissues?

epithelial

where is epithelial tissue typically found?

on surfaces

what consists of epithelial tissue?

sheet like layers of cells usually connected by tight junctions with little ECM between them

It also covers body surfaces and surfaces of internal organs, lines cavities and ducts within the body

what secretes ECM?

basal lamina

what is the outer surface of epithelium called?

apical surface which is typically exposed to water, air, or fluids within the body

what is the inner epithelium surface called?

the basal surface which adheres to a layer of ECM which fixes the epithelium to underlying connective tissues

in internal cavities and ducts the apical surface is typically covered with?

cilia which move fluids through the cavity or duct

in some epithelia including the lining of the small intestine the free surface is covered with?

microvilli which are fingerlike extensions of the plasma membrane that increase the area available for secretion or absorption

what is the function of microvilli?

increase the area of absorption/ secretion

what is the function of cilia?

move fluids

epithelia are classified as?

simple( formed by a single layer of cells)

or

stratified (formed by multiple cell layers)

cell shapes within an epithelium may be?

- squamous (flattened)

- cuboidal (cube shaped)

- columnar (elongated)

what is simple squamous epithelium?

layer of flattened cells found in blood vessel walls, or air sacks of lungs which function for diffusion

what are the 4 principal types of epithelium found in the body?

- simple squamous

- stratified squamous epithelium

- cuboidal epithelium

- columnar epithelium

what is stratified squamous epithelium?

several layers of flattened cells typically found in areas with surfaces subject to abrasion

what is cuboidal epithelium?

layer of cubelike cells whose free surface may have microvilli. Typically found in glands and tubular parts of nephrons in kidneys whose function is for secretion and absorption

what is columnar epithelium?

layer of tall slender cells whose surface may have microvilli. Typically found in the lining of the gut and respiratory tract and functions for secretion and absorption

How do some epithelial cells divide rapidly?

by stem cells in the basal layer of the skin

what are stem cells?

undifferentiated cells that divide to produce more stem cells or differentiating cells that become specialized body cells

where are stem cells found?

adult: the brain, bone marrow, blood vessels, skeletal muscle, and the liver

also found in embryos

what are glands?

epithelia which give rise to cells specialized for secretion

what are exocrine glands?

ducts connected to the epithelium by a duct which empties their secretion at the epithelial surface

what are endocrine glands?

ductless glands that release hormones which are distributed by the circulatory system

what does connective tissue do?

supports other body tissues, transmits mechanical and other forces and in some cases act as filters

what makes up connective tissue?

cells form networks or layers in and around body structures separated by nonliving ECM

many forms of connective tissue have more?

ECM than cellular material by weight and volume

the mechanical properties of a connective tissue depend on the?

type and quantity of its ECM

consistency of ECM ranges from?

fluid, through firm gels, to hard and crystalline

what does ECM consist of in most tissues?

fibrous glycoprotein collagen embedded in a network of proteoglycans

what is fibronectin?

another family of glycoproteins that aids in attachment of cells to ECM and helps hold cells in position

what is the function of elastin fibers?

help some connective tissues return to their original shape when pulled or stretched

where is the protein resilin found?

only in insects and some crustaceans and is the most elastic material known

what are the 6 types of connective tissue?

loose

fibrous

cartilage

bone

adipose

blood

what does loose connective tissue consist of?

sparsely distributed fibroblast cells surrounded by an open network of collagen and other glycoprotein fibers

what are mesenteries?

sheets of loose connective tissue that holds abdominal organs in place and provide lubricated, smooth surfaces that prevent chafing or abrasion

what is dense connective tissue made of?

fibroblasts are sparsely distributed among dense masses of collagen and elastin fibers that are lined up in highly ordered, parallel bundles

what is cartilage made of?

sparsely distributed chondrocytes surrounded by networks of collagen fibers embedded in a tough elastic matrix of the glycoprotein chondroitin sulfate

what is the function of cartilage?

Support, flexibility, low-friction surface for joint movement

what is mature bone made of?

osteocytes embedded in an ECM containing collagen fibers and glycoproteins impregnated with hydroxyapatite

what is the function of osteoblasts?

produce collagen and minerals

what is the function of osteoclasts?

remove minerals and recycle them through the bloodstream

what is the structural unit of bone?

the osteon which is a central canal surrounded by osteocytes embedded in concentric layers of mineral matter

where do blood vessels and extensions of nerve cells run through in bones?

the central canals

what is adipose tissue made of?

densely clustered adipocytes that are specialized for fat storage - it has little ECM

what is the major transport vehicle of the body?

blood

blood cells are suspended in?

fluid ECM (plasma)

what are erythrocytes?

red blood cells packaged with hemoglobin that binds and transports oxygen

what are leukocytes?

(white blood cells) protect the body against invading viruses, bacteria, and other pathogens

what are platelets?

(membrane-bound fragments of specialized blood cells) participate in blood clotting

what two proteins cause contractions in muscles?

actin and myosin

cells in skeletal muscle are?

multinucleate and striated (actin and myosin molecules are arranged in parallel units that give the tissue a banded appearance)

cells in cardiac muscle are?

short and branched, with each cell connected to neighboring cells at intercalated disks

cells in cardiac muscle form?

an interlinked network, stabilized by anchoring junctions and gap junctions, which enables heart muscle to contract in all directions

cells in smooth muscle are?

small and spindle-shaped, and their actin and myosin molecules are arranged in a loose network (smooth rather than striated

cells in smooth muscle are connected by?

gap junctions that allow them to contract as a unit

what are glial cells?

physically support and provide nutrients to neurons, provide electrical insulation between them, and scavenge cellular debris and foreign matter

what is the function of ECF in multicellular organisms?

receives nutrients and O2, and eliminates wastes

what are the two components or ECF?

Plasma, the fluid portion of blood

Interstitial fluid, the fluid that surrounds the cells

what connects the intracellular fluid to the external environment?

the ECF as it acts as a transitional zone

how does nutrients and O2 in the plasma reach the Interstitial fluid?

through the capillaries and waste moves in the opposite direction

how do regulator species function?

maintain factors of the internal environment in a relatively constant state

how do conformer species function?

have internal environments that match the external environment

what are the steps of negative feedback control?

stimulus

sensor

integrator

effector

compensatory response that acts back to return conditions to the set point and stop stimulus

return

what is a positive feedback mechanism?

a mechanism that intensifies or adds to the change

what is an alteration of the normal set point called?

acclimatization

when a set point is changed in a laboratory it is called?

acclimation

what is a hormone?

Regulatory chemical that is secreted into extracellular fluid and carried by the blood

Can act at a distance from source

what are the two basic characteristics of a hormone?

1. Must be sufficiently complex to convey regulatory information to their target cells

2. Must be adequately stable to resist destruction before reaching their target cell

what are the characteristics of paracrine regulators?

•do not travel in blood

•allow cells of organ to regulate each other

what are the characteristics of autocrine regulators?

secreted by the same cell as the receptor target

what are the characteristics of pheromones?

• chemicals released into the environment to communicate among individuals of a single species

•Not involved in normal metabolic regulation within an animal

what are the 4 classes of signaling molecules?

amine

steroid

peptide

fatty acid

what are the characteristics of amine hormones?

classical endocrine and neuroendocrine signaling

hydrophilic (polar) binding to cell surface receptors

most based on tyrosine

what are examples of amine hormones?

dopamine, epinephrine, norepinephrine

What's the one exception for amine hormones that isn't hydrophilic?

thyroxine which is hydrophobic passing through the plasma membrane and binding to a receptor inside the target cell

what are the characteristics of peptide hormones?

classic endocrine and neuroendocrine signaling

amino acid chains

some have carb groups

released into blood or ECF

can act in paracrine and autocrine

what are the characteristics of steroid hormones?

classic endocrine signaling

hydrophobic (non-polar) bind inside target cells

carried by carrier proteins to form water-soluble complexes

what are some examples of steroid hormones?

aldosterone, cortisol, sex hormones

what are the characteristics of fatty acid derived hormones?

paracrine and autocrine signaling

increase contractions of smooth muscles especially in the uterus

induce contraction or relaxation of smooth muscle cells in blood vessels and air passages in the lungs

intensify pain and inflammation in injured cell regulation

what's an example of fatty acid derived hormones?

prostaglandins

what are the two categories of hormones?

1. Lipophilic (nonpolar) -fat-soluble

Steroid hormones and thyroid hormones

Travel on transport proteins in blood

Bind to intracellular receptors

Tend to have much longer active period

2. Hydrophilic (polar) -water-soluble

All other hormones

Freely soluble in blood

Bind to extracellular receptors

Tend to act over brief time period