32.1 Nutrients and Homeostasis KEY CONCEPT Cells require many different nutrients.

32.1 Nutrients and Homeostasis

KEY CONCEPTCells require many different nutrients.


The six types of nutrients are water, carbohydrates, proteins, fats, minerals, and vitamins.

• Water makes up 55% to 60% of your body. – involved in nearly every cell and body process– need 2 liters (8 cups) a day to replace fluid lost


• Carbohydrates are the main source of energy for the body.– simple and complex carbohydrates supply glucose– fiber from plant foods helps elimination

Simple and Complex Carbohydrates


• Proteins are necessary for growth and repair of the body’s cells.– body makes 12 out of 20 amino

acids – other eight essential amino acids

come from food• Fats provide energy and key

building components.– fats are saturated and

unsaturated – essential fatty acids come from

food

Proteins and Fats


• Minerals are inorganic materials.– help to build or repair tissues– replenished by eating variety of foods


• Vitamins are organic molecules that work with enzymes.– vitamins are fat-soluble and water-soluble – regulate cell functions, growth, development – replenished by eating variety of foods


Meeting nutritional needs supports good health.

• During puberty, you require more nutrients and Calories.– One Calorie equals one

kilocalorie, or 1000 calories. – 1g of protein or carbohydrate

equals 4 Calories. – 1g of fat equals 9 Calories.


• A balanced diet of whole foods provides the best nutrients and Calories.

• Food and physical activity also need to be balanced. MALES

FEMALES


• Food labels can help you make good eating choices.


KEY CONCEPTThe digestive system breaks down food into simpler molecules.


mouth

esophagus

liver

gallbladder

large intestine

small intestine

rectum/anus

Several digestive organs work together to break down food.

• The digestive system breaks down food into energy cells can use.

• After digestion is complete, nutrients are absorbed and transported to all cells.

• Undigested materials are eliminated as liquid and solid wastes.


Digestion begins in the mouth and continues in the stomach.

• Mechanical and chemical digestion break down food. • Peristalsis moves food through the organs.

esophagus

muscles contract

muscles relax

food

stomach


• Digestion of carbohydrates begins in the mouth.

• Digestion of proteins occurs in the stomach. • Digestion of fats and sugars occur in the

small intestine.


Digestion is completed in part of the small intestine.

• Most digestion takes place in the duodenum. • The pancreas, liver, and gallbladder aid in digestion.

– pancreas helps digest fat and protein – bile from the liver/gallbladder helps digest fats

liver

bile

bile

gallbladder

duodenum

pancreas

enzymes

chyme

stomach


KEY CONCEPTNutrients are absorbed and solid wastes eliminated after digestion.


Most absorption of nutrients occurs in the small intestine.

• Three structures in the small intestine help absorb nutrients. – folded lining: adds surface area, slows food– villi: absorb nutrients– microvilli: cover villi, absorb nutrients


• Duodenum, jejunum, and ileum absorb different nutrients.

• Nutrients enter the circulatory or lymphatic systems. • Liver stores excess glucose for future use.

liver

small intestine


Water is absorbed and solid wastes are eliminated from the large intestine.

• The colon helps to maintain the body’s fluid balance.• Undigested material forms the solid feces.

– stored in rectum – eliminated through anus

large intestine

rectum/anus


• The large intestine contains many bacteria.– some synthesize important vitamins– Some, like E. coli, can cause illness


KEY CONCEPTThe excretory system removes wastes and helps maintain homeostasis.


The excretory system eliminates nonsolid wastes from the body.

• Nonsolid wastes are eliminated through lungs, skin, and kidneys.

• Lungs exhale carbon dioxide and water vapor.

• Sweat glands in skin release excess water and salts.

• Kidneys filter and clean the blood to produce urine.

skin

lungs

kidneys

ureters

urinary bladderurethra


The kidneys help to maintain homeostasis by filtering the blood.

• Kidneys are a pair of bean-shaped organs.– two layers: medulla and

cortex– filtering units called

nephrons – renal artery and renal

vein

cortex

medulla

renal artery

renal vein

ureter

(to bladder)


• Kidneys have three basic functions in maintaining homeostasis.– remove waste from blood– help to maintain electrolyte, pH, and fluid balances – release key hormones


Nephrons clean the blood and produce urine.

• Nephrons are the filtering units in the kidneys.• They clean and rebalance the blood to produce urine.

from body

to body

to body

from other nephrons

loop of Henle


• Nephrons clean the blood in a three-step process.• The first step is filtration of the blood.

FILTRATION

Water,electrolytes,aminoacids,glucose,urea, and other small molecules diffuse out of the blood,creating the filtrate.

1

Glomerulus

Bowman’s capsule


• The first step is filtration of the blood. • The second step is reabsorption of materials.• The third step is excretion of materials.

from body

to body

collecting duct

from other nephrons

loop of Henle

REABSORPTION

As the filtrate enters the rest of the tubule ,most of the materials are reabsorbed into the blood.Materials not reabsorbed make up the urine,which flows into the loop of Henle.

2

EXCRETION

In the loop of Henle,water can be reabsorbed one final time to reduce the volume of urine.The remaining urine flows into a collecting duct that leads to the ureter.

3


Injury and disease can damage kidney functions.

• A kidney transplant can replaced damaged kidney. – recipient and donor tissue must match – drugs prevent tissue rejection

The daughter and son in this photo donated a kidney and liver tissue to their mother.


• Dialysis can be used to filter and clean the blood.

32.1 Nutrients and Homeostasis KEY CONCEPT Cells require many different nutrients.

Documents

Transcript of 32.1 Nutrients and Homeostasis KEY CONCEPT Cells require many different nutrients.