Biology - Unit 4: Animals - Structure & Function

Carbohydrates

• main source of energy

• stored as glycogen in liver, excess is converted into lipids and stored as body fat

• vegetables, potatoes, grains

Proteins

• transporting oxygen

• hormones

• defense (antibodies)

• source of energy

• meat, fish, eggs, cheese

Lipids

• absorption of vitamins

• main component of cell membrane

• insulation

• concentrated source of chemical energy

• oily fish (e.g. salmon), nuts, seeds

Water

• cell cytoplasm

• maintain blood volume

• regulate body temperatures

• maintain skin moisture

Vitamins

• regulates cell functions, growth, and development

Minerals

• carries out metabolic processes

• builds and repairs tissues

• fruits, vegetables

Monosaccharides

• single sugar moleclue

• e.g. glucose, fructose

Dissaccharides

• 2 monosaccharides

• e.g. lactase, sucrose

Polysaccharides

• 3+ monosaccharides

• e.g. cellulose, starch, glycogen

Saturated Fats

• all single-bonded carbons

Unsaturated Fats

• has 1+ double-bonded or triple-bonded carbons

Fat-Soluble Vitamins

• soluble in lipids

• A, D, E, K

• not easily excreted and can be toxic in excess

Water-Soluble Vitamins

• soluble in water

• B, C

• more easily excreted, primarily through urine

Mechanical Digestion

• physical breakdown of food

Chemical Digestion

• chemical breakdown of food

Teeth & Jaws

• tear and grind food into smaller pieces

Tongue

• taste

• keeps food in place to chew

• pushes food to back of the mouth when swallowing

Papillae

• pimple-like structure that houses tastebuds

• covers the surface of the tongue

Salivary Glands

• secretes saliva to moisten and digest food

Saliva

• watery liquid with enzymes and mucus

Mucus

• forms bolus

• lubricates food

• aids in swallowing

• protects pharynx and esophagus

Amylase

• breaks bonds in polysaccharides to form disaccharides

Uvula

• ball-like tissue hanging at the back of the mouth

• prevents entry of food into the nose

Soft palate

• back of the roof of the mouth

• raised when swallowing, prevents bolus from entering nasal passages

Epiglottis

• flap-like tissue that covers the glottis

• prevents entry of food into the larynx

Glottis

• opening of the larynx

• space between vocal cords

Larynx

• voicebox

• when raised, causes epiglottis to cover the glottis

• large space between vocal cords when breathing

• muscles contract when speaking, closing gap between the cords

Pharynx

• area in the throat that connects the oral and nasal cavities with the esophagus and larynx

• guides food to the esophagus

• guides air to the trachea

Esophagus

• contracts to push food down

Peristalsis

• wave-like muscle contractions that pushes the bolus into the stomach

Stomach

• churns food

• secretes highly acidic gastric juices and enzymes

Gastroesophageal Sphincter

• near esophagus

• controls movement of food into the stomach

Pyloric Sphincter

• near duodenum

• controls movement of chyme into the small intestine

Mucosa

• has rugae

• secretes enzymes, acids, and mucus

Submucosa

• contains nerves and blood vessels

• detects presence of food, releases gastrin (a hormone)

Muscularis

• muscle layer that frequently contracts to churn food

Serosa

• secretes lubricating fluid to eliminate friction between organs

• holds stomach in place

Duodenum

• U-shaped, first 25-30 cm of small intestine

• enzymes added, chemical digestion

Jejunum

• 2.5m long

• has more folds and intestinal glands

• has villi

Villi

• increases surface area, maximizes absorption

Microvilli

• microscopic projections on the villi

• maximizes surface area

Lacteals

• lymphatic vessels

• absorbs and transports fats into the lymphatic system

Ileum

• 3m long

• absorbs most nutrients

• pushes remaining undigested material into the large intestine

Ileocecal Valve

• controls movement of undigested material into the cecum

• prevents backflow

Pancreas

• secretes digestive enzymes - amylase, lipase, trypsin

• neutralizes the acidity of chyme

Lipase

• breaks down lipids

Trypsin

• breaks down proteins

Liver

• largest internal organ

• produces bile

• removes and breaks down toxins that were absorbed by blood in the intestinal capillaries

Gallbladder

• stores and releases bile into the duodenum

Large Intestine

• larger in diameter than the small intestine, but shorter in length

Cecum

• pouch that receives chyle

Colon

• absorbs water, vitamins, electrolytes

• ascending, transverse, descending, sigmoid

• bacteria chemically digests food and produces some vitamins

Rectum

• lower 20 cm of large intestine

• stores feces (undigested food)

Bile

• emulsifies (breaks down) fats

Anus

• opening that eliminates digestive wastes

Internal Anal Sphincter

• involuntary, controls anal opening

External Anal Sphincter

• voluntary, controls anal opening

Nasal Passages

• turbinate bones - increase surface area

• mucus - moisten air

• capillaries - warm and moisten air, protects lung tissue

Turbinate Bones

• curved, bony structures inside the nasal cavity

Trachea

• flexible tube

• supported by semicircular rings of cartilage, prevents tube from collapsing

Bronchi

• one bronchus enters each lung

• transports air to bronchioles from the trachea

Bronchioles

• finer tubules

• mucus moistens air

• transports air to alveoli from the bronchus

Alveoli

• gas exchange, mostly via diffusion

• grape-like cluster of sacs

• always moist

• surrounded by a network of capillaries

Diaphragm

• contracts during inhalation

• relaxes during exhalation

Lungs

• structure for respiration in vertebrates

Pleura

• membrane surrounding the lungs

• secretes a lubricating fluid

• protects the lungs

Intercostal Muscles

• between ribs

• moves the ribcage upwards and outwards

External Respiration

• gas exchange between atmosphere and blood via diffusion

Hemoglobin

• a protein in RBCs that binds oxygen and carbon dioxide

Internal Respiration

• gas exchange between cells and blood

• occurs in capillaries

Inhalation

• diaphragm and intercostal muscles contract

• lung volume increases, air pressure in lungs decrease, oxygen enters body from the atmosphere

Exhalation

• diaphragm and intercostal muscles relaxes

• lung volume decreases, air pressure in lungs increase, carbon dioxide leaves the body to the atmosphere

Tidal Volume

• the volume of air that can be inhaled/exhaled in a normal, involuntary breath

Inspiratory Reserve Volume

• the amount of air that can be forcibly inhaled after a normal inhalation

Expiratory Reserve Volume

• the amount of air that can be forcibly exhaled after a normal exhalation

Vital Capacity

• the max amount of air that can be exhaled after fully inhaling

Total Lung Capacity

• the max volume of air that the lungs can hold at their maximum expansion

Arteries

• carries blood away from the heart

• thick muscular walls

• elastic, fibrous tissue

• smaller in diameter

• largest artery - aorta

Veins

• carries blood to the heart

• thin muscular walls

• one-way valves

• larger in diameter

• largest veins: superior vena cava and inferior vena cava

Capillaries

• smallest blood vessels

• gas exchange via diffusion

Blood Pressure

• force exerted by blood against the walls of blood vessels

• recorded as systolic/diastolic

• normal is 120/80

Sphygmomanometer

• a device that measures blood pressure

Systolic Pressure

• pressure in blood vessels during contraction of the heart

Diastolic Pressure

• pressure in blood vessels during relaxation of the heart

Vasoconstriction

• narrowing of blood vessel, decreases blood flow, increases blood pressure

• due to contraction of muscle cells in blood vessel walls

Vasodilation

• widening of blood vessel, increases blood flow, decreases blood pressure

• due to relaxation of muscle cells in blood vessel walls

Blood

• medium for transport of gases and nutrients

• 55% plasma, 45% cellular components

Red Blood Cells

• transports oxygen, carbon dioxide, and nutrients

• no nucleus (in later stages)

• contains hemoglobin

White Blood Cells

• fights foreign agents

Platelets

• helps to clot after injury

• fragments of cells (megakaryocytes)

Plasma

• mostly water

• dissolved gases and nutrients

Coronary Circulation

• pathway of blood within the heart

Pulmonary Circulation

• pathway of blood between the heart and lungs

Systemic Circulation

• pathway of blood between the heart and the rest of the body

Arterioles

• small arteries

Venules

• small veins

Heart

• muscular organ made up of 2 separate pumps

• underneath sternum

• on the left side of the thoracic cavity

Atria

• collects blood returning to the heart

• left and right atria contract simultaneously

• smaller than ventricles

Ventricles

• larger than atria

• left and right ventricles contract simultaneously

• left ventricle has thicker walls