Fetal Pig Dissection Prep

A Review of Major Organs and Organ Systems

1

The Digestive System

■ Every cell requires a constant supply of nutrients and energy.

■ i.e. food

■ DIGESTION – the breakdown of food by mechanical and chemical means.

■ The digestive tract and the accessory organs of digestion make up the digestive system

■ The DIGESTIVE TRACT is a hollow tube extending from the mouth to the anus

■ It is also called the ALIMENTARY CANAL or the GASTROINTESTINAL (GI) TRACT

The Digestive Tract…■ Structures of the digestive

tract: ■ Mouth (oral cavity) ■ Pharynx (throat) ■ Esophagus ■ Stomach ■ Small intestine ■ Large intestine ■ Rectum ■ Anus

The Accessory Organs…■ The accessory

organs include: ■ Salivary glands ■ Teeth ■ Tongue ■ Liver ■ Gallbladder ■ Pancreas

Mouth■ The digestive tract

begins with the MOUTH, also known as the ORAL CAVITY or BUCCAL CAVITY

Mouth■ The mouth contains structures that

assist in the digestive process: ■ Teeth ■ Tongue ■ Salivary glands ■ Hard palate ■ Soft palate

Teeth■ MASTICATION –

the process of chewing

■ Teeth rip and grind food

Tongue■ TONGUE – a muscular

organ that occupies the floor of the mouth ■ Mixes food ■ Pushes the food toward the

pharynx ■ Taste buds allow us to enjoy

food ■ Speech forming consonants ■ Lingual frenulum: fold of

membrane that secures tongue to floor of mouth

Tongue■ Tongue-tied: distorted speech due to

shortened frenulum

Salivary Glands3 pairs of SALIVARY GLANDS secrete their contents into the mouth ■ AMYLASE enzyme to begin breakdown of starch ■ Cleanses mouth ■ Antibodies to inhibit bacteria

Pharynx■ The tongue pushes

the food from the mouth into the PHARYNX (throat)

■ The pharynx is involved in swallowing

Esophagus

■ ESOPHAGUS – a long tube that carries food from the pharynx to the stomach

Stomach

■ Stomach: C-shaped organ

■ Lies in the abdominal cavity, just under the diaphragm

Functions of the stomach…1. digestion of food 2. secretion of gastric (stomach) juice, which

includes digestive enzymes, and hydrochloric acid as its most important substances

3. secretion of gastric hormones and intrinsic factor

Regions of the stomach…■ FUNDUS ■ BODY ■ PYLORUS

Regions of the stomach…Two sphinctors ■ PYLORIC

SPHINCTOR regulates the rate that gastric contents are delivered to the small intestine

Regions of the stomach…■ CARDIOESOPHAGEAL

SPHINCTER ■ Between esophagus and

stomach

Small intestine■ Chyme enters in

small amounts due to pyloric sphincter ■ Most food is absorbed

in small intestine ■ High surface area

Large Intestine■ Larger diameter,

shorter in length ■ Dries out food by

absorbing water ■ Eliminates food

residue (feces)

■ Cecum ■ Appendix ■ Ascending colon ■ Transverse colon ■ Descending colon ■ Sigmoid colon ■ Rectum ■ Anal canal ■ Anus

Liver

■ Liver: large, reddish-brown organ located in the upper abdominal cavity

■ All blood from digestive system enters liver first

■ HEPATIC refers to liver

Liver ■ Produces bile to break up (emulsify) fat ■ No bile or lipase, no fat absorption ■ Detoxification of drugs ■ Metabolism of carbohydrates, proteins,

fats

Gallbladder■ Located underneath

liver

■ Stores bile

■ Gallstones: crystallized bile

Pancreas■ Both endocrine and exocrine

secretions ■ The exocrine secretions include

digestive enzymes ■ Most important of all digestive

enzymes

Pancreas■ Enzymes

■ Amylase: carbohydrate breakdown ■ Lipase: fat breakdown ■ Trypsin, chymotrypsin, peptidases: protein breakdown ■ Nucleases: nucleic acid breakdown

Pancreas■ Hormones

■ Insulin: brings glucose into cells

■ Glucagon: releases glycogen from liver

Organs of the respiratory system■ Nasal cavity ■ Nasopharynx ■ Larynx ■ Trachea ■ Bronchi ■ Lungs

Nose and Nasal Cavities

■ Sense of smell ■ Warms the air ■ Mucus to trap bacteria & debris ■ Ciliated cells move mucus toward throat ■ Separated from mouth by the palate

Pharynx – the Throat

■ Includes:

1. Nasopharynx

2. Oropharynx

■ The pharynx conducts food toward the esophagus and air to the larynx

Larynx

■ Also called the VOICEBOX is located between the pharynx and the trachea

Has 3 functions: 1. Passageway for air 2. Produces sound 3. Prevents food and other

foreign objects from entering the trachea

■ Food and water should not enter the larynx

■ How is food and water kept out of the larynx?

■ At the top of the larynx is a hole called the GLOTTIS

■ When you breathe in air, the glottis opens, and air moves through the glottis into the lungs

■ When you swallow food, a flap called the EPIGLOTTIS covers the glottis, sending food instead into the esophagus, preventing food from entering the respiratory passages

Trachea■ Also called the

WINDPIPE ■ Splits into the right/left

BRONCHI (plural), BRONCHUS (singular)

■ Conducts air to and from the lungs

■ Rings of hyaline cartilage maintain shape

Lungs■ Two LUNGS, located

in the thoracic cavity, extend from just above the clavicles to the diaphragm

■ Subdivided into lobes

■ Right lung has 3 lobes

■ Because of the location of the heart in the left side of the chest, the left lung only has 2 lobes

Lungs■ Alveloi

■ Site of gas exchange

■ The DIAPHRAGM is a muscle that forms the floor of the thoracic cavity and separates the thoracic cavity from the abdominal cavity

■ It is the chief muscle of respiration

The Heart and Cardiovascular System

Heart■ Hollow, muscular

organ made of cardiac muscle

■ Function: pump blood through the blood vessels of the body, providing every cell in the body with nutrients and oxygen

Pericardium■ The pericardium is

a serous membrane, secreting a slippery fluid into the pericardial space

Heart

■ The heart has 4 chambers: 2 atria and 2 ventricles

■ The ATRIA (singular ATRIUM) receive the blood – the upper chambers

■ The VENTRICLES pump the blood out of the heart – the lower chambers

Heart Chambers

The Endocrine System

Endocrine System■ Communicates through CHEMICAL

SIGNALS called HORMONES

■ Responds more slowly and generally exerts longer-lasting effects than the nervous system

Thyroid Gland■ THYROID GLAND –

located in the anterior neck

■ Thyroid hormone- controls rate at which glucose is burned

■ Calcitonin- deposits calcium into bone

Thymus■ Large in infants and

decreases size as adults

■ Programs T lymphocytes

Spleen ■ Immune system ■ Filters blood

Gonads ■ The GONADS are the sex glands

■ OVARIES in females

■ TESTES in males

■ The gonads not only produce eggs and sperm, they secrete hormones as well

Scrotum■ Holds the testes

outside of pelvic cavity

■ Sperm production must happen at a lower temp than body temp

Uterus■ Functions to receive

and nourish a fertilized egg

Urinary System■ Kidneys ■ Ureters ■ Urinary bladder ■ Urethra

Kidneys ■ Kidney bean shaped

organs ■ Under 12th rib ■ Cleanse blood of

waste products ■ Makes urine

Ureters ■ Tubes from kidney to

bladder

Urinary Bladder■ Sac that stores urine

Urethra ■ Carries urine from

bladder to outside