Human Biology

Chapter 1

Anatomy +Physiology

anatomy

  • cutting open

  • structure parts

Physiology

  • how a living organism performs their vital functions

Homeostasis - 3 components

  1. receptor

    • sensitive to stimuli

    • detects

  2. control centre

    • receives + process info

    • decides what to do

  3. effector

    • respond to the commands of the control centre

  • eg; temperature control

Feedback loops

Negative- returns the body to normal conditions by acting against the stimulus; homeostatic mechanism

  • variation outside normal limits triggers a corrective response

Positive- reinforces the stimulus, leads to a goal

  • blood clotting

  • labour

Directional Terms

  • dorsal-ventral

  • distal-proximal

  • medial-lateral

  • superior-inferior

Planes of section

  • frontal

  • sagittal

  • transverse

  • need not be through the centre

Body Cavities

  • lined with serous membranes to reduce friction

    • visceral

    • parietal

  • pleura

  • pericardium

  • peritoneum

Chapter 2

Chemical Level of Organization

Most of our body is composed of just a few elements

  • oxygen, carbon, hydrogen, calcium, phosphorous, potassium, sodium, chlorine, magnesium, sulfur, iron, iodine

  • organic molecules are comprised of mainly H,C, O

  • inorganic do not have C-H bonds

  • Most Ca and P are found in bones but play important roles elsewhere

Polar Bonds: unequal sharing of electrons

  • atoms with the same electronegativity share a non-polar bond

  • a C-H bond is also non-polar

  • atoms with unequal electronegativity form polar bonds

  • that may make the whole molecule polar

  • polar molecules dissolve better in water “like dissolves like”

A small portion of water will exist in ionic form

  • ions are charged

    • either lacking (cations)

    • or extra electrons (anions)

  • normal water formula

  • a proton (H+) can be transferred to another water molecule to form

  • the remaining ion

  • other molecules can add or remove H+ to or from water

  • the concentration of H3O+ determines the pH

pH scale

  • pH = concentration of hydrogen ions

  • log scale

  • acids s bases

  • 7.0 neutral

Hydrolysis vs Dehydration Synthesis

Hydrolysis: water can be added to bonds to break them

Dehydration: water can be removed to form bonds

3 major chemical structures

carbohydrates

  • C, H, O (1:2:1)

  • important as an energy source

  • monosaccharides: one simple sugar

    • glucose

  • disaccharides: 2 monosaccharides joined together

    • dehydration synthesis necessary

    • sucrose

  • polysaccharides: 3+ monosaccharides together

    • starches, cellulose, glycogen

  • used for hydrolysis (water to break down)

    • A complex molecule is broken down by the addition of a water molecule

lipids

  • C, H, O (1:2:less oxygen)

  • non-polar bonds

  • don’t dissolve well in water

  • fatty acids are the basic subunit

    • 3 fatty acids combine with glycerol to form triglycerides, aka fats

    • these are stored in our fat cells, adipocytes

    • long term energy storage

  • fatty acids combine to form other lipids

    • 2 fatty acids with a glycerol to form diglycerides

    • 3rd position contains a polar group

    • one end is polar, the other non-polar

    • these make up cell membranes

  • steroids are a type of lipid

    • primary steroid is cholesterol

      • minor component of cell membranes

      • converted to steroid hormones

        • estrogen, progesterone testosterone, cortisol

Proteins

  • C, H, O, N

  • composed of

    • hydrogen group

    • amino group (-NH3)

    • Carboxyl group (-COOH)

  • amino acdis are subunits

    • 20 diff amino acid groups

    • combine by dehydration synthesus to form peptide bonds

    • proteins are made of polypeptides, some thousands of amino acids long

    • structure and function dpeend on nature fo the R groups

    • proteins can be catalysts, strucural, messengers, cause movement

  • Nucleiic acids carry info

    • te subunit is a nucleotide which contains

      • sugar

      • phosphate

      • base

    • these combine to forma. suagr-phosphate backbone, with ethe base protruding

    • the bases are

      • adanine

      • guanine

      • cytidine

      • thymine / uracil

    • RNA is single stranded, dna forms a double helix

    • base pairing occurs

    • strands are anti-parallel

    • sequence provides information

    • RNA sequense is copies form DNA

      • contains U instad of T

  • ATP stores energy

    • atp has a sugar(ribose), base (adeniine) and 3 phosphates

    • phosphate bonds release energy wen broken

    • this energy is used to drive other reactions in the cell

    • energy is needed to conert adp to atp

      • comes from breakdown of other molecules in cell

      • energy released drives other reactions in the cell

Chapter 3

Cell structure and function

  • Cell theory

    • cells are the building blocks of all plants and animals

    • cells are the smallest functioning units of life

    • cells are produced through the division of pre-existing cells

    • each cell maintains homeostasis

  • cells come in many different shapes and sizes

    • all derived form a single fertilized egg

    • all contain the same DNA

      • except blood cells, they are reproduced not duplicated

    • some continue to divide, others don’t

    • all enclosed within a plasma membrane

  • Membrane is essential for cell function

    • transport occurs across the memebrane

      • nutrients

      • wastes

      • signaling molecules

    • membrane contains structures relating to cell function

      • micro villi

      • cilia

  • membrane contains lipids, proteins and carbohydrates

    • phospholipids form bilayer

    • proteins can be integral or associated with membrane

      • transport across membrane

        • lipid soluble, dissolve through plasma membrane

        • diffusion

          • concentration

      • receptors for signaling

      • adhesion

    • carbohydrates on exterior

      • glycolipids

      • glycoprotiens

      • identificatio

        membrane transport

      • difusion

      • substances fo down in concetration gradientg

        • difference between high and low concentrations

      • simple diffusion is passive

        • cross membrane directly

        • lipid soluble molecules

      • facilitated diffusion

        • requires protein carriers

        • includes channels- aqua porins

        • may be gates

  • osmosis

    • facilitates diffusion of water

    • aquaporins- water channels

    • water molecules tend to flow across a membrane toward the solution containg the higher solute concentration

    • osmotic pressure (water)

    • force that drives water through memebrane

    • solutes may differ across the membrane

    • as the solute concentration of a sollution increases, so does the osmotic pressure

    • physical pressure may drive water against osmotic pressure

      • important in fluid exchange for capillaries

    • affects cell size

    • wrinkly fingers in water

      • low concentration in fingers- higher in water

      • osmotic pressure drives fluid to fingers

      • only fingers because not all cells are water soluble

      • increased fluid in outer cells, but cant get through everywhere

  • active transport

    • substances go up in concentration gradient

    • energy is required - usually atp

      *sodium potassium pump

    • essential for cell function

    • sodium (Na) is pumped out

    • potassium (K) is pumped in

    • voltage gradient forms

Endocytosis moves large molecules into cell by vesicular transport

  • receptor-mediated transport

    • targets specific substances

    • clusters in vesicles

    • after delivery vesicle is returned to cell membrane

  • phagocytosis (specialized type)

    • protective function against pathogens

    • cell extends and engulfs substances

    • vesicle combines with lysosomes to add digestive enzymes

    • undigested contents are returned to outside

Exocytosis - leaving secretion

  • secreted proteins, neurotransitters, glucose etc

  • membrane compoonents are recycles by combination of endocytosis/exocytosis

Cell surfaces contain microvilli and cilia

  • microvilli

    • shorter, nonmotile

    • increase surface area

    • absorption in intestinees

  • cilia

    • longer, motile

    • move mucus in airways

    • some are sensory, nonmotive

cytoskeleton performs different functions

  • microfillaments

    • near the surface

    • cell shape changes

  • intermediate filaments

    • stable

    • connect with adhesion molecules

  • microtubles

    • intracellular transport

centriolles

  • made of microtubles

  • located next to nucleus

  • microtuble organizing centre

    • intracellular transport

    • mitosis

most atp is made in mitochondria

  • function as energy powerhouse

  • final stages of metabolism

  • requires O2, produces CO2

  • cutting off oxygen for ATP is like putting a lid on a candle

Nucleus stores information as DNA

  • chromatin

    • DNA is coiled around histone proteins for packaging

    • chromatin is further condensed in mitosis

information in DNA is copies in Transcription

  • transcription- RNA makes copy

  • occurs in nucleus

  • DNA helix opens

  • RNA copies

  • becomes mRNA, has info for protein

  • DNA closes

Information on mRNA is transplated to make protein

  • occurs in cytoplasm on ribosomes

  • requires tRNA to transfer amino acid to growing protein

  • utlizes genetic code

  • ribosomes may be free or bound to endoplasmic reticulum

Endoplasmic Reticulum ER

  • transcription in nucleus

  • mRNA in nucleus

  • translation occurs on ER

    • protein production

    • rough vs smooth

    • vesicles move to golgi apparatus

Golgi apparatus

  • functions

    • j

Cell cycle 4 Stages

  • normally stay in G1

  • need a stimulus to enter S phase

  • in G2 cells prepare for mitosis

DNA replicated in S phase

  • both strands copied in opposite directions

Cells divide in mitosis

  • prophase

    • longest phase

    • centrioles duplicate seperate

    • nuclear membrane dissolves

    • replicated DNA condenses into chromosomes

  • metaphase

    • chromosomes line up in centre

  • anaphase

    • chromitids seperate

  • telophase

    • nuclear membrane reforms

  • cytokinesis

    • cells seperate

Chapter 4 - Tissues

4 types of tissues

  • epithelial

    • provide protectioin

    • may/may not be permeable

    • no direct blood supply

    • glands are specialized epithelia

      • exocrine- have ducts

      • endocrine- secrete into blood- insulin

    • structure

      • exposed surface

      • distinct polarity

      • may have projections on surface

      • attached to basement membrane

      • attached to each other

    • joined by junctions

      • tight- prevent leaking between cells

      • gap- communication between cells

      • desmosomes- hold cells together

        • spot desposomes

        • hemidesmosomes

        • adhesion belt

    • classification

      • cell shape

        • squamous- flat, usually permeable

          • simple- lining blood vessels, lungs, body cavities

        • cuboidal- secretory

          • glands, ducts thyroid

        • columnar- absorptive

          • intestines, gallbladder

          • number of layers simple stratified- multiple layers

        • stratified squamous

          • skin, mouth, anus, vagina

          • stem cells replace dying cells

          • only surface cells are squamous

        • pseudostratified

          • multiple cell types, looks stratified but isn’t

          • nasal cavity, trachea, bronchi

        • transitional

          • stretches, in contact with urine

          • glands are modified epithelia

        • endocrine or exocrine

          • endocrine= products discharged through blood/tissue fluids

          • exocrine=products discraged thorough a duct/tube

        • modes of secretion

          • merocrine -

          • apocrine -

          • holcrine -

  • connective

    • functions

      • support and protectin

      • transportation of meterials

      • storage of energy reserves

      • defense of the body

    • 3 components

      • specialized cells

      • extracellular fibers

      • ground substance

    • 3 types of connective tissue

      • connective tissue proper

      • fluid connective tissue

      • supporting connective tissue

  • muscle

  • neural