Lymphatic and Digestive Systems Anatomy Definitions

Flashcards covering definitions of terms related to the lymphatic and digestive systems.

Lymphatic System

A network of tissues and organs that helps the body get rid of toxins and fight infections. It includes lymph, lymph nodes, and lymph vessels.

Leukocytes

Cells that protect the body by fighting infections and foreign substances.

Neutrophils

The most common white blood cell; they quickly attack bacteria and are the first to arrive at an infection.

Eosinophils

White blood cells that fight parasites and play a role in allergic reactions.

Basophils

The rarest white blood cells; they help with allergic reactions by releasing histamine.

Monocytes

Large white blood cells that turn into macrophages and clean up dead cells and germs.

Lymphocytes

White blood cells that are key to the immune response; they include B cells and T cells.

B Cells

Make antibodies to attack bacteria and viruses outside the cells.

T Cells

Kill infected cells directly and help control the immune response.

Hemopoietic Cells

Stem cells in bone marrow that produce all blood cells, including red, white, and platelets.

Lymph

A clear fluid that travels through the lymphatic system, carrying white blood cells and waste.

Lymphatic Ducts

Large tubes that drain lymph into the bloodstream.

Lymphatic Capillaries

Tiny vessels that collect lymph from tissues.

Lymph Nodes

Small, bean-shaped filters that trap germs and cancer cells; they also contain immune cells.

Thymus Gland

An organ in the chest where T cells mature; it’s most active in children.

Red Bone Marrow

Spongy tissue inside bones where blood cells are made, including white blood cells.

Spleen

An organ that filters blood, removes old blood cells, and helps fight infections.

Mucosa-Associated Lymphatic Tissue (MALT)

Clusters of immune tissue found in areas like the gut and respiratory tract; they protect mucous membranes from infection.

Mouth

The opening where digestion begins; teeth break food down, and saliva starts chemical digestion.

Esophagus

A muscular tube that moves food from the mouth to the stomach.

Foregut

The upper part of the digestive tract, including the esophagus, stomach, liver, and first part of the small intestine (duodenum).

Midgut

The middle section of the digestive tract, including the rest of the small intestine (jejunum and ileum) and the first part of the large intestine.

Hindgut

The last part of the digestive tract, including the rest of the large intestine (colon, rectum) and the anus.

Esophageal Hiatus

An opening in the diaphragm that the esophagus passes through to reach the stomach.

Gastrointestinal (GI) Tract

The continuous tube from the mouth to the anus where digestion and absorption of food occur.

Stomach

A muscular organ that churns food and mixes it with acid and enzymes to start breaking it down.

Duodenum

The first part of the small intestine where most digestion happens; receives food from the stomach and enzymes from the pancreas.

Jejunum

The middle part of the small intestine where nutrients are absorbed.

Ileum

The last part of the small intestine; absorbs leftover nutrients and passes material to the large intestine.

Villi

Tiny finger-like projections in the small intestine that increase surface area for absorbing nutrients.

Cecum

A pouch at the start of the large intestine that receives food from the ileum.

Colon

The main part of the large intestine; absorbs water and forms stool.

Rectum

The final section of the large intestine that stores stool before it leaves the body.

Peritoneum

A thin membrane that lines the abdominal cavity and covers abdominal organs.

Greater Omentum

A large, fatty layer of tissue that hangs over the intestines like an apron; it helps protect and cushion organs.

Lesser Omentum

A smaller tissue layer that connects the stomach and liver.

Mesenteries

Folded tissues that anchor the intestines to the back wall of the abdomen and carry blood vessels to them.

Mucosa

The inner lining of the GI tract that comes in contact with food; helps absorb nutrients and secrete mucus.

Lamina Propria

A layer of connective tissue under the mucosa that contains blood vessels and immune cells.

Muscularis Mucosae

A thin layer of smooth muscle that helps move the mucosa and increase contact with food.

Submucosa

A thicker layer of connective tissue that contains blood vessels, nerves, and glands.

Muscularis Externa

Two layers of smooth muscle (circular and longitudinal) that contract to move food through the digestive tract.

Serosa

The slippery outer covering of the GI tract that reduces friction as organs move.

Submucosal Plexus

A network of nerves in the submucosa that controls secretions and blood flow in the gut.

Myenteric Plexus

A network of nerves between the muscle layers of the muscularis externa that controls muscle movement and gut motility.

Esophageal Arteries

Small arteries that supply blood to the esophagus.

Celiac Trunk

A major artery that branches off the aorta and supplies blood to the stomach, liver, spleen, and part of the small intestine.

Superior Mesenteric Artery

Supplies blood to most of the small intestine and the first part of the large intestine.

Inferior Mesenteric Artery

Supplies blood to the lower part of the large intestine (hindgut).

Hepatic Portal Vein

Carries nutrient-rich blood from the digestive organs to the liver for processing.

Salivary Glands

Produce saliva to moisten food and begin digestion.

Sublingual Salivary Glands

Located under the tongue; produce mostly mucus-rich saliva.

Submandibular Salivary Glands

Found under the jaw; produce a mix of watery and mucus saliva.

Parotid Salivary Glands

Located near the ears; produce watery, enzyme-rich saliva.

Liver

The body’s largest internal organ; makes bile, stores nutrients, and detoxifies blood.

Porta Hepatis

The 'gateway' of the liver where blood vessels, bile ducts, and nerves enter and exit.

Gallbladder

A small organ under the liver that stores and releases bile to help digest fat.

Bile Duct

A tube that carries bile from the liver and gallbladder to the small intestine.

Pancreas

Produces digestive enzymes and hormones like insulin; helps break down food in the small intestine.