Unit 4 - Animal Systems

Nutrients

Nutrients

Chemicals needed by the body and found in the foods that we eat

• to get energy

• support physiological functions

• provide raw materials for growth and repair

Types of nutrients

• Carbohydrates

• Vitamins

• Lipids

• Minerals

• Protein

• Water

Macronutrients

needed in large amounts

• Carbohydrates

• lipids

• proteins

Micronutrients

needed in small amounts

• vitamins

• minerals

Carbohydrates

organic compounds made of carbon, hydrogen and oxygen

• Source of energy

• Cell structure

Monosaccharides

Mono = 1

Saccharide = sugar

• Simple carbohydrates

• E.g. glucose, fructose, galactose, ribose

• Quick source of energy because they do not have to be digested and can be used directly

Disaccharides

Di = 2 “double sugar”

• Simple Carbohydrates

E.g.

1. glucose + fructose = sucrose

2. glucose + galactose = lactose (“milk sugar”)

3. glucose + glucose = maltose (“malt sugar”)

Polysaccharides

Many linked monosaccharides

• Complex Carbohydrates

• E.g. starch (plants), cellulose (plants), glycogen (animals), chitin (fungi and animals)

Starch

Polysaccharide made and stored in plants

• branched chain of glucose and molecules

• chemical bonds are weak and easily broken down by animals

Glycogen

Polysaccharide made and stored in animals

• branched chains of glucose molecules

• stored in liver and muscle or converted to fat

• part of regulating glucose levels in the blood

Cellulose

Polysaccharide found in cell walls of plants

• Glucose subunits form a straight rigid structure

• indigestible in humans

Chitin

Polysaccharide found in the cell walls of fungi and the exoskeletons of arthropods such as insects and crustaceans (crabs, lobsters, and shrimps)

Lipids

Organic compounds containing fatty acid chains

• Concentrated energy source (used after carbohydrates for endurance activities)

• Component of cell membrane

• Absorption of vitamins

• Insulation and temperature regulation

Fatty Acids

Long hydrocarbon chains ending with - COOH (carboxyl)

Saturated

• fatty acids

• single bonds

• Solid at room temperature

• Butter and high-fat cuts of meat

Unsaturated

• fatty acids

• 1 or more double or triple bonds

• liquid at room temperature

• avocado oil, peanut oil, olive oil, as well as fish such as salmon

• 2 types: monounsaturated and polyunsaturated

Monoglycerides

• glycerides

• one fatty acid molecule attached to a glycerol molecule

• produced when fat is digested

Diglycerides

• glycerides

• 2 fatty acid molecules attached to a glycerol molecule

• produced when fat is digested

Triglycerides

• glycerides

• 2 fatty acid molecules attached to a glycerol molecule

• vegetable oils and animals fats contain mostly triglycerides

Phospholipids

Component of all cell membranes

1. phosphate head

2. glycerol backbone

3. fatty acid tails

Sterols

Occur naturally in plants, animals and fungi

E.g. cholesterol

Ring structure

Proteins

Made up of 30+ amino acids (most abundant organic compound in body)

• structure (muscles, hair, nails)

• enzyme production

Complete protein

• amino acids

• food that contains all essential a.a.

• e.g. meat, fish, eggs, dairy

Incomplete protein

• amino acids

• lacks one or more essential a.a.

• E.g. plant foods - flour, rice cereals, beans, peas, nuts

Vitamins

organic substances made of C, H, O, N, and small amounts of other elements

• regulate cell functions

• Growth and development

  Most are coenzymes

Coenzymes

join to enzymes to ensure that biological reactions properly

Fat soluble vitamins

• Vitamins A, D, E, and K

• will dissolve in fats

• stored in liver and fatty tissue

• cannot be excreted (over time break down as they are used up by the body)

• Not needed on a daily basis (can be toxic in large quantities)

• Vitamins A, D, and K can be produced in our bodies

Water-Soluble Vitamins

• Vitamins B and C

• Excess excreted in urine

• not stored in body for long

• Daily intake recommended however too large of a dose may put a strains on the kidneys

Minerals

Inorganic chemical elements

• forms structural part of bone

• structural parts of hormones and enzymes

• controls water balance of cells

• control blood pH

• involved in the transmission of nerve impulses

Major minerals

required in large amounts

• Ca, P, Cl, K, Mg, Na, S

• Ca + P = tooth and bone formation

• Na = muscle contraction

Trace minerals

required in small amounts

• Co, I, Se, Cu, Fe, Si, Cr, Mo, Sn, Mn, Ni, F, Zn, V

• Fe = found in hemoglobin

Water

A body’s need for water is 2nd in importance only to its need for oxygen.

Adult body is approximately 55-60% water

• involved in chemical reactions in the body

• Digestion

• Eliminate waste

• maintain blood volume

• regulate body temperature

• keep skin and organs hydrated

Digestive System

Breaks down food in order to release nutrients that the body’s cells can absorb and use, while excreting the remaining waste

Gastrovascular cavity

A digestive sac with a single opening in simple animals like flatworms and jellyfish

Complete digestive system

2 opening for food intake and waste elimination in complex animals like earthworms and humans

The mouth

• teeth physically break food down

• enzymes in saliva chemically break food down

• Saliva contains the enzyme amylase which breaks starch (carbs) into simple sugars as well as mucus

• mucus acts a a lubricant and aids in swallowing

• the tongue pushes food (bolus) to the pharynx at the back of the mouth so that it can be swallowed

The esophagus

• epiglottis, a flap of soft tissue, covers the trachea when swallowing to prevent food from entering the lungs

• once swallowed, the bolus of food moves into a muscular tube connecting the mouth and stomach called the esophagus

• smooth muscle contracts to move food along the digestive tract in wavelike contractions called peristalsis

The stomach

• food passes through the gastroesophageal sphincter and into the J-stomach where it is churned and proteins and partially digested

• A sphincter is a circular muscle which contracts and relaxes

• There are 50+ sphincters in the human body

• The stomach produces gastric juice made of mucus, enzymes and hydrochloric acid

• The mixture of food and gastric juice is called chyme

Gastroesophageal sphincter

when relaxed, allows food in the stomach

when contracted, keeps food from moving back into the esophagus

Mucosa

• inner layer

• Folded layer that secretes gastric juice

Sub-mucosa

contains blood vessels and nerves

Muscularis

smooth muscle that contracts frequently to churn food

• oblique muscle

• circular muscle

• longitudinal muscle

Serosa

• Outer layer

• Holds stomach in place and secretes lubricating fluid to avoid friction with other organs

Nerves

in the submucosa detect food is present and initiate the release of gastrin

Gastrin

a hormone released into the bloodstream and transported to the stomach, which it stimulates the release of gastric juice

Gastric juice

a liquid made of mucus, acid, and enzymes

Hydrochloric acid

• pH: 2.0-3.0

• kills micro-organisms

• Strops the action of amylase

• activates another digestive enzyme pepsinogen

Pepsin

pepsinogen is converted to pepsin, an enzyme which breaks down proteins

Acid Reflux

• occurs when the gastroesophageal sphincter does not close properly or the stomach is overfilled

• Causing acid to enter the esophagus

• Creates a burning sensation in lower throat

• heartburn

Ulcer

• With limited mucus, the stomach lining is exposed to stomach acid and and open sore (ulcer) develops

• Helicobacter pylori is a bacterium that can survive in the acidic stomach by secreting acid-neutralizing enzymes and preventing mucus producing cells to protect the stomach lining

The small intestine

• 6-7m in length

• this narrow tube is where digestion and absorption of nutrients occurs

• Lipids and carbohydrates, as well as remaining proteins, are digested here

Duodenum

Most enzymes added here and digestion begins

Jejunum

digestion continues and some nutrients are absorbed

Ileum

Majority of nutrients are absorbed in this final section

Villi and Microvilli

• The inner layer of the small intestine is folded into ridges (villi)

• Each villus has a smaller projection called microvilli

• Allows for an increased surface area for nutrient absorption

• Molecules enter the bloodstream via capillaries within each villus

• All nutrients enter the bloodstream with the exception of digestion fats which are transported via lacteals

Trypsinogen

• an inactive enzyme

• Pancreas also secretes it

• travels from the pancreas to the duodenum

Enterokinase

an enzyme that converts trypsinogen to trypsin

trypsin

• an active protein-digesting enzyme

• continues the work begun by pepsin in the stomach, further breaking down partially digested proteins

Carboxypeptidase and erepsin

enzymes that further break down proteins into individual amino acids

Lipases

Lipids are emulsified by bile from the gall bladder and further digested in the duodenum by lipases

• a group of enzymes secreted by the pancreas

Absorption in the small intestine

macro and micronutrients are absorbed in the jejunum and ileum. These nutrients travel from the villi into the blood stream

Passive Transport

Does not require energy

Diffusion

movement of nutrients from high concentration to low concentration

• passive transport

• E.g. small amino acids

Osmosis

Movement of water from high concentration to low concentration

• Passive transport

Facilitated diffusion

Transport proteins that are embedded in the cell membrane help specialized molecules across the membrane

• E.g. disaccharides

• Passive transport

Active Transport

• requires energy

• molecules move from low concentration to high concentration

• transport proteins move large molecules and ions that cannot diffuse through the cell membrane

The large intestines (colon)

• at about 1.5m in length

• the lining of this wider tube absorbs water from undigested and indigestible food (such as cellulose) and as well as some vitamins and ions

• Any waste is subsequently eliminated from the body as feces during egestion

• It takes 4-72 hours for material to pass through the large intestine

• More than 500 species of bacteria inhabit the large intestine

• some even play a role vitamin B and K production

Cecum

receives processed material from the small intestine

• it has a small projection called the appendix which does not serve any digestive function in modern humans

Ascending, transverse, descending, and sigmoid colon

absorption of water, vitamins, etc.

Rectum

holds waste

Anus

external opening where waste is eliminated

Liver

• an accessory organ

• produces a fluid called bile which helps to breakdown fat

• bile emulsifies fats, breaking them into tiny droplets called micelles

• also begins the removal and breakdown of toxins, such as alcohol

• stores glycogen and fat-soluble vitamins

Gall bladder

stores the bile produced by the liver, and releases it into the duodenum when lipids enter the small intestine

Pancreas

The long, flat gland secretes enzymes involved in digestion and hormones that regulate the absorption and storage of glucose from the blood

Respiratory System

works with the circulatory system to provide oxygen and remove carbon dioxide from the body. You breathe in and out approximately 15 times/min.

Cellular Respiration

C₆H₁₂O₆ + 6O₂ + 36 ADP + 36P_i → 6CO₂ + 6H₂O + 36ATP + thermal energy

Thermal Energy

64% of energy released which helps mammals maintain a constant body temperature

Adenosine Triphosphate (ATP)

• where 36% of energy is stored. Powers almost all energy-requiring processes, like growth and movement. (3 phosphate groups)

• Forms when ADP (2 phosphate groups) is phosphorylated (a phosphate group attaches to ADP) as glucose is broken down

• When ATP reacts with other molecules and loses this phosphate group this phosphate group (reforming ADP, back to 2 phosphate groups), energy is released

Features of Respiratory System

1. A thin permeable respiratory membrane through which diffusion can occur

2. A large surface area for gas exchange

3. A good supply of blood

4. A breathing system for bringing oxygen-rich air to the respiratory membrane

Composition of Air

• 78% nitrogen 

• 21% oxygen

• 1% argon

• 0.04% CO₂

• Lesser amounts of other gasses

Respiratory system mouth and nose

Air is warmed, moistened, and filtered as it enters through the mouth and nasal passages (lined with hair and mucus).

Respiratory System pharynx and epiglottis

Pharynx connects the mouth and nasal passages with the esophagus and trachea. The epiglottis covers the trachea and prevents food from entering the windpipe.

Respiratory System Larynx

There are 2 folds of tissue inside called the vocal cords which tighten as you speak and as you breathe out, the air passing over them causes them to vibrate.

Respiratory System Trachea

A muscular tube wrapped in bands of cartilage which keep the windpipe open. It is lined with sticky mucus and cilia to trap particles.

Respiratory System bronchi (bronchus)

The trachea branches into 2 bronchi (right and left) which connect to each lung.

Respiratory System Bronchioles

Each bronchus branches into many bronchioles, which connect to a cluster of alveoli.

Respiratory system Alveoli

Surrounded by capillaries for gas exchange.

Gas Exchange in the respiratory system

• between the respiratory and circulatory system occurs in the alveoli.

• Alveoli have thin walls and are surrounded by capillaries. There are approximately 150 million alveoli per lung

• Provides necessary surface area for gas exchange 

• When air is inhaled, oxygen diffuses into the bloodstream, where it travels to tissues in the body

• CO₂, a byproduct of cellular respiration, diffuses out of the bloodstream and is exhaled

Ventilation Mechanics

breathing is based on the principle of negative pressure. Air moves from an area of higher pressure to an area of lower pressure (V ↑ the P ↓)

Inhalation

The diaphragm and intercostal muscles contract, lung volume increases, air pressure in lungs decreases, air flows into the lungs (20.94% O₂, 0.04% CO₂)

Exhalation

The diaphragm and intercostal muscles relax, lung volume decreases, air pressure in the lungs increases, forcing air out of the lungs. 916.49% O₂, 4.49% CO₂)

Medulla oblongata

the area of the brain that controls the involuntary breathing, which detects the concentration of CO₂ in the blood

Pleural membranes

lining of the lungs and thoracic cavity which reduce friction during ventilation

Pneumothorax

when a lung collapses if air gets between the pleural membranes

Total Lung Capacity

(~6 L) - the max volume of air that can be inhaled during a single breath

Tidal Volume

(~0.5 L) - the volume of air moved in a normal breath at rest

Vital Capacity

 (~3.5 L for females and 4.5 L for males) - the max volume of air that can move in and out of lungs.

Residual Volume

the volume of air that is remaining in the lungs after a forced exhalation

VO₂

the rate at which oxygen is used in the body

VO₂ max

the max amount of oxygen an individual can use (mL/kg/min), which can be measured using a spirometer or fitness testing.