Bio Final Exam

The four steps that involves Nutrition in all Organism

Acquisition of nutrients

DIgestion, if required

Distribution of nutrients throughout the body

synthesis of molecules for the organism’s body

What is one of the main functions in Animals

Nutrition, it act as a energy source

plants

Starting material- Elements and small molecules

Digestion-Usually none

Distribution-driven by osmosis and evaporation

Synthesis of molecules- Can do it all

Animals

Starting Material-Large organic molecules

Digestion-Required to break large molecules down to building blocks

Distribution-Pumping mechanism for most

Synthesis of molecules- Must acquire some through diet

What large organic molecules filled with for Animals

Energy

What is nutrient energy measured in

Calories (amount of energy needed to raise the temperature of gram I gram of water by 1 degree celcius)

What is food energy content measured in

Calories.  1 Calorie = 1 kilocalorie (1000 calories).

How many calories does an adult

1500 calories per day at complete rest

Exercise (and mental activity) greatly boosts caloric requirements

The five major categories of animal nutrients are

Lipids, carbohydrates, Proteins, Minerals, and Vitamins

Lipids /Fats

Provides more energy/gram than any other nutrient source

Fat (9 calories/gram)

Carbohydrates or proteins (4 calories/gram)

Advantages of Fats

We store our “extra” calories as fats

-more calories with less weight (3600 Calories/pound)

            -fats are hydrophobic and do not cause accumulation of water

            -functions as insulation because fat conducts less heat (see fig 35-2)

 

Fats supply certain hormones, Cell components(membranes), nerve cell coverings

What Fatty acid is essential to humans

linoleic acid

Carbohydrates/Sugars

The principal energy storage molecules in plants

Animals also store carbohydrates as a quick energy source.  In the liver and muscles of humans carbohydrates are stored as glycogen (animal starch)

Proteins

Provide the amino acids building blocks for the construction of proteins

Of the 20 amino acids that are commonly found in proteins in humans 10 either cannot be synthesized by our bodies or are made in too low of an amount and must be supplied by our diet.

 

These amino acids are essential amino acids

 

Specialized amino acids also act as hormones and neurotransmitters.

Minerals

Like plants, animals require these small inorganic molecules.  We obtain most from food or drinking water.

 

 

Essential Minerals (see table 35-1)

 

            -bones (calcium, magnesium, phosphorus, fluorine)

            -teeth (calcium, magnesium, phosphorus, fluorine)

            -nerve impulse conduction (sodium, potassium, chlorine)

            -muscle contraction (sodium and potassium)

            -oxygen transport (iron for hemoglobin)

Vitamins

Diverse types of organic compounds needed in small amounts

Most cannot be made by humans (except Vitamins D) and therefore must be supplied by our diet

Two categories of Vitamins

Waters- soluble -vitamins cannot be stored and must be continually supplied

Vitamin C and B

Fat-soluble -vitamins are stored in body fats

Vitamins A (forms pigments for vision) , Vitamins D,E,K ( needed for normal blood clotting)

Not True

If a little is good, then a lot must be better

Vitamins A and D are toxic if intake is excessive.

five functions that a digestive system must accomplish

            Ingestion

            Mechanical breakdown

            Chemical breakdown

            Absorption

            Elimination

Ingestion

usually through a mouth

Mechanical breakdown

 food is broken into smaller pieces

Gizzards, Teeth, Churning action of digestive cavity

 

Chemical breakdown

Digestive fluids and enzymes

Absorption

Transport of small nutrient molecules from the digestive system to the cells

Elimination

Expelling indigestible materials from the body

Two basic types of digestive systems

Intracellular digestion

Extracellular digestion

Intracellular Digestion

Digestion within a single cell, Found in sponges and protists

involves endocytosis(food intake), formation of a food vacuole, digestion of the food by lysosomes, and exocytosis (waste dumping)

Extracellular Digestion

varies from digestion in a simple sac to digestion in a tube open at both ends and running through the body

All use a gastrovascular cativy. All of these variations use a gastrovascular cavity.  The cells lining the gastrovascular cavity engulf small particles or absorb molecules.

Human Digestion

Begins in the mouth where mechanical and chemical breakdown of food begins.

32 adult teeth

3 pairs of salivary glands

Saliva functions

    Contains the enzyme amylase which begins breaking down starch to sugars

Kills some bacteria with antibiotics.

  Lubricates food

  Dissolves some food molecules so the taste buds in the tongue can recognize

them.

The tongue manipulates the food into a mass and pushes it back to the pharynx

Pharynx

Connects mouth and the esophagus

Epiglottis

blocks the opening to the trachea while directing the food to the esophagus

Esophagus

A muscular tube connecting mouth and stomach

In the esophagus, more mucus further lubricates the food that is pushed along by peristalsis (sequential contractions of circular muscles)

Stomach

An expandable muscular sac

Three major functions:storage chamber, Mechanical breakdown of food, Chemical digestion

The storage chamber function

Accomplished by a ring of muscles between stomach and small intestine (pyloric sphincter) that acts to regulate the passage of chyme (partially digested food and digestive secretions) into the small intestine.

Churning of the stomach

The churning of the stomach continues the mechanical breakdown that was begun by the mouth.

The chemical breakdown comes from chemicals secreted by the stomach

Gastrin, Hydrochloric Acid, Pepsinogen

Gatrin

a hormone that stimulates the secretion of hydrochloric acid by specialized stomach cells.

Persinogen

the inactive form of a protease (an enzyme that breaks proteins into smaller peptides).  The pepsinogen is converted to the active form (called pepsin) by the hydrochloric acid in the stomach

Why doesn’t the stomach self-digest

The reason the stomach doesn't self-digest is because of a protective layer of mucus which is continuously secreted by glands.  If this layer breaks down (do to abuse or infection) an ulcer can occur (see page 669)

Peristaltic waves

Peristaltic waves, about 3 per minute, move chyme into small intestine about a teaspoon per contraction

When will a stomach empty

2-6 hours

Little absorption

Occurs through the stomach:  water, alcohol, and some drugs. A full stomach slows alcohol absorption

What occurs in small intestine

Most digestion and nutrient absorption

Small intestine

1-2 inch diameter and about 10 feet long

What aid the digestion process

Secretions from the liver, pancreas, gall bladder and small intestine cells

What is the largest organ in digestive tract

The liver

Liver role in digestion

Produces bile stores it in the gallbladder, and releases it into small intestine

through the bile duct

Bile

a complex mixture of bile salts, other salts, water and cholesterol

Bile Salts

Act as detergents or emulsifying agents to disperse fats so they can be digested further.

The Pancreas has 2 types of cells

            -produces the hormones insulin and glucagon for blood sugar regulation

 

-produces digestive pancreatic juices

The pancreatic juices contain

            Sodium bicarbonate that neutralizes the acidic chyme.

            Three types of digestive enzymes:

                        Amylases: break down carbohydrates.

                        Lipases: break down fats.

                        Proteases: break down proteins and peptides

Proteases:

convert peptides into amino acids

Sucrase, lactase, and maltase

convert disaccharides into monosaccharides

Absorption in the small intestine

aided by the presence of villi and microvilli along the inside on the small intestine.

Final absorption of water and salts

The result is a semisolid feces consisting of indigestible wastes and dead bacteria are transported by peristalsis to the rectum where defecation occurs.

Homeostasis

Homeostasis - tendency of life to try and maintain the structure and regulate the internal environment

The excretory system

Restores and maintains the proper internal regulation of these materials in the body despite differences in diet

major functions of the excretory system in mammals

Excretion of cellular waste products, Regulation and maintenance of body fluid composition Ions, water and nutrient, Secretion of hormones

Urea

A compound that removes ammonia from the blood

urea compound

Protein >> amino acids >>> simpler molecules + ammonia

Flame cells

Tubes ends at hollow bulbs

In flatworms are the simplest excretory system -network of tubes branching throughout the body

Nephridia

in earthworms and mollusks function as simple kidneys

In the earthworm nearly every segment contains a pair of nephridia

Nephrostomes

Funnel-shaped openings where coelomic fluid enters the nephridia.

3 Major Functions of the Excretory System (mammals)

1. Excretion of cellular waste products
2. Regulation and maintenance of body fluid composition (ions, water, nutrients)
3. Secretion of hormones

Kidneys

Filters blood and produces urine
-Complex organs that resemble a dense collection of nephridia
-Paired, bean-shaped organs
-About 5x3x1 inch
-Have a large surface area where nutrients are selectively reabsorbed and wastes and some water are left behind to form urine
-Regulates water absorption

Excretion in humans and other vertebrates is accomplished by the ____________ and the ______________ _______________.

kidneys; urinary system

Unfiltered blood enters through the renal _____________ and filtered blood leaves through renal ____________.

arteries; veins

Ureter

Passes urine by peristalsis to the bladder

Bladder

Hollow muscle that stores and collects urine

Urethra

Where urine is emptied

The retention of urine in the bladder is controlled by 2 _______________ muscles.

sphincter

The first sphincter opens ____________________. Due to...

involuntarily; receptors in the bladder walls trigger reflexive contractions

The second sphincter opens _____________________.

voluntarily

The average adult bladder can hold about a ________ of urine.

pint

Urination

-Both sphincter muscles at the bladder's base relax
-The bladder contracts, forcing urine down the urethra

What senses bladder fullness?

Stretched receptors

Where urine forms in the solid outer layer of the kidneys

Nephrons

2 parts of the outer layer of the kidneys

Cortex, Medulla

Hollow inner chamber of the kidneys that funnels the urine into the ureter.

Renal Pelvis

3 parts of a nephron

1. Glomerulus
2. Bowman's capsule
3. Tubule

Glomerulus

A filter for blood

Bowman's Capsule

Collects the filtrate (fluid filtered from the blood)

3 parts of the tubule (in nephron)

1. Proximal Tubule
2. Loop of Henle
3. Distal tubule that leads to collecting duct

1. _____ conduct blood to each nephron

Arterioles

Within Bowman's capsule the arteriole subdivides into a capillary network called the _____

glomerulus

The glomerulus capillary walls are _____ to water and dissolved substances

permeable

The _____ filtrate, resembling blood plasma minus the proteins, is collected in Bowman's capsule for transport through the nephron

watery

The blood leaving the the glomerulus in the arteriole is much more ______, containing blood cells, proteins and fat droplets too big to be filtered out.

concentrated

These arterioles then branch into smaller highly porous _____ that surround the tubule.

capillaries

___ ____ occurs as the blood reabsorbs water and nutrients from the filtrate.

Tubular reabsorption

Any waste materials remaining in the blood are actively _____ into the tubule

secreted

During its passage through the collecting duct, additional water leaves the filtrate by ____ until the urine reaches equilibrium with the highly concentrated surrounding fluid.

osmosis

How many times do the kidneys filter a human's blood a day?

350

What happens when the kidneys fail?

Death

Over ____ gallons of water enter the Bowman's capsule daily. Most is ___________________ through _______________.

reabsorbed; osmosis

Antidiuretic Hormone (ADH)

-AKA vasopressin
-Regulates how concentrated urine becomes and how much water is reabsorbed
-ADH levels in the blood increases permeability of the distal tubule and collecting duct to water.
-Made by the hypothalamus in response to receptor cells there (that monitor the concentration of the blood) and in the heart (monitor blood volume)

When the concentration of blood rises or blood volume falls, __________ ADH is released.

more

What does drinking beer do

-Causes dilution in the blood and increase in blood volume

-The bladder fills faster and the urine is much less concentrated.

3 lines of defense against microbial attack

1. External barriers
2. Innate immune response (non-specific)
3. Adaptive immune response (specific)

External barriers

Skin and Mucous Membrane