Unit 1: Digestive System, Cellular Respiration, Tissues, and Organs

Tissues, Organs, Digestive System, + Cellular Respiration

Levels of Organization

1) molecules

2) organelles

3) cells

4) tissue

5) organs

6) organ systems

7) organism

tissue

a group of cells working together

organs

structures composed of multiple tissues working together for 1 function

Organ Systems

multiple organs working together for a specific function

1) different organ systems in organisms interact a lot

Organism

something made up of multiple organ systems

anatomy

the name/identity of something

1) typically organs

physiology

the function of something

1) typically organs

digestive system

takes in food and gets nutrients into the body

respiratory system

exchange gases with the environment

circulatory system

supplies oxygen and nutrients to the whole body

lymphatic/imune system

1) lymphatic: diverts substances to be thoroughly inspected by the body

2) immune: keeps us safe from dangerous foreign bodies.

excretory system

removes waste

endocrine system

maintains homeostasis

nervous system

sends and receives signals from the outside world

integumentary system

body covering (skin)

skeletal system

responsible for movement, support, and protection

muscular system

responsible for movement, support, and protection

reproductive system

sexul reproduction

Tissue Types

1) epithelial

2) connective

3) muscle

4) Nervous

Epithelial Tissue

linings and coverings

1) does secretion and absorption

2) also protective

3) structures: squamous, cuboidal, columnar and simple or stratified

squamous

epithelial tissue with flat cells

cuboidal

epithelial tissue with cube-like cells

columnar

epithelial tissue with column-like cells

simple tissue

1 layer

1) maximizes diffusion

2) not trying to protect

3) ex: lining of intestine

connective tissues

binds and supports other tissues

1) has many functions (ex: cartilage connects muscles to bones.)

2) contain matrix

3) there are fibrous and loose connective tissues

matrix

non-lining material secreted by cells to help bind and support other cells

1) is how we tell the difference between different connective tissues

fibrous connective tissue

connective tissue with high levels of collagen in matrix but not much elastin.

1) Need have less elastin in order to be tighter

2) two types: tendons and ligaments

tendons

connect muscle to bone

ligaments

connect bone to bone

collagen

makes tissue resistant and resists stretching

elastin

makes tissue more easily stretched

loose connective tissue

connective tissue with lower amounts of collagen and higher amounts of elastin.

1) stretchier

muscles

responsible for movement

1) three muscle types: skeletal, smooth, and cardiac

skeletal muscle

Muscle connected to the bone

1) under voluntary control

1) has contractile units (sarcomeres) responsible for striations (the stripes)

2) activation of a single part contracts the whole fiber (moves as a unit)

4) strong

5) structure is extremely regular; easier to move as one

sarcomere

contractile units of muscles

1) responsible for striations

smooth muscle

on walls of digestive tract, bladder, arteries, etc.

1) has sarcomeres under the plasma membrane (non-visible)

2) contraction is weaker but can be sustained for longer

3) like a smooth, elastic sheet

4) no striations

5) not voluntarily controlled

cardiac muscle

surrounds the ykw

1) responsible for pumping

2) has sarcomeres and striations

3) branched for transmission and signaling

4) shorter but stronger

nervous tissue

senses stimuli and transmits info from 1 part to another

1) has long extensions that help it do that

2) ex: nuerons and glial

neurons

nervous cells responsible for the transmission of info; communication network

1) can be very long

glial cells

surround + support neurons

Digestive System

organ system responsible for ingestion, digestion, absorption, and elimination

Ingestion

getting food into the body

digestion

breaking down polymers into monomers

1) has 2 parts: mechanical and chemical digestion.

mechanical digestion

separating food into chunks; big chunks → little chunks

chemical digestion

hydrolysis/the chemical separation of polymers into monomers (H2O is required)

1) required for absorption to occur

absorption

actually taking in the monomers

elimination

disposing of the waste (pooping)

protease

enzymes that digest proteins

amylases

enzymes that digest polysaccharides

nucleases

enzymes that digest nucleic acids

lipases

enzymes that digest fatty acids

1) fats start digestion the latest out of all of the enzymes because are digested in the small intestine

mouth/teeth

1) do mechanical digestion

salivary glands

1) produce saliva and enzymes for chemical digestion

2) mostly produce amylases

saliva

the beginning of polysaccharide digestion

pharynx

entrance to the respiratory system and the tubular section of the digestive system

epiglottis

the flap over the trachea

1) opens and closes to allow air in

esophagus

transport food from the pharynx to the stomach

stomach (structure)

does chemical and mechanical digestion

1) includes the cardiac sphincter, gastric sphincter, and duodenum (kinda)

cardiac sphincter

closes at the top of the stomach

1) keeps acid in the stomach

gastric sphincter

closes at the bottom of the stomach

1) keeps acid in the stomach

duodenum

the start of the small intestine

1) transports chyme from the stomach to the small intestine

liver

secretes bile

bile

emulsifies fats to aid digestion (helps them mix with digestive liquids)

1) also neutralizes chyme

gall bladder

stores bile

pancreas

1) produces digestive enzymes

2) produces pancreatic juice

3) produces hormones

small intestine

does chemical digestion absorption

1) has chemicals + enzymes from liver + pancreas and its epithelial tissue

2) has a lot of length/surface area to maximize absorption

3) absorbs nutrients into blood and the lymphatic system

nutrients absorbed by blood

monosaccharides, amino acids, and nucleotides

nutrients absorbed by lymphatic system

fatty acids

structure of the small intestine

1) extremely long to increase surface area for absorption and time for chemical digestion

2) has many folds to increase surface area per section of the lining

3) has villi and microvilli

villi

finger-like projections/units of absorption on the folds of the small intestine

1) has its own blood supply and lymphatic system

microvilli

mini villi on the villi

large intestine

reabsorbs water and is a bacteria microbiome

1) called the “large” intestine because is greater in diameter

2) made up of the ascending, transverse, and descending colon.

3) hosts a lot of bacteria; most of it is helpful for us. 700+ species

3) distributes water back into the blood stream

bacteria in the large intestine

1) facilitates chemical digestion

2) synthesizes vitamins (ex: vitamin K)

3) have many other functions

4) dangerous if the balance is off

stomach (function)

for the digestion of proteins

1) proteins are difficult to digest because of the tertiary structure/2nd folding + peptide bonds are hard to break

2) secrets pepsin (enzyme) and HCl acid (strong)

chyme

patrially digested food

self digestion (explanation)

1) HCl acid is really strong, so the stomach needs to protect itself

2) the stomach s made of proteins but also digests proteins, so could potentially eat itself

structures to prevent self digestion

1) sphincters

2) mucus

3) hormone gastrin

4) (bonus) epithelium constantly replaces itself through mitosis

sphincters

close to stop stomach acid from escaping

mucus

basic (pH) snot-like structure produced by the stomach for protection

hormone gastrin

regulates acid release

1) makes sure acid is only being produced when food is being consumed

2) has negative feedback loop (stops producing if there’s enough)

3) produced by the stomach for the stomach

parietal cells

cells in the stomach lining that produce pepsinogen

chief cells

cells in the stomach lining that produce HCl

pepsinogen

the inactive form of pepsin

1) becomes pepsin when in contact with HCl

pepsin

a protease found in the stomach

1) breaks down proteins

gastric glands

glands in the stomach lining that produced hormone gastrin

Stomach Acid

HCl

1) softens food

2) denatures proteins for easier digestion

3) activates pepsinogen (optimal range turns it into pepsin)

4) kills bacteria on food

rectum

last part of the large intestine where things are stored until releasing fecal matter.

apendix

the vestigial structure at the start of the large intestine