Glands And Membranes (ch 3) Flashcards
Why is there a limit on cell size?
An overly large sell cannot support itself, it may rupture
Cell structure: plasma membrane
Aka cell membrane Surrounds cells, defines boundaries Made of proteins and lipids Governs interactions with other cells Controls the passage of materials in and out of the cell
Cell structure: cytoplasm
Organelles
Cytoskeleton
Inclusions (stored or foreign particles)
Cytosol (intracellular fluid/ICF)
Cell structure: extracellular fluid
fluid outside of cells - includes ground substance
What is the purpose of cell junctions?
They are connections between two cells
They are anchored to each other or to the matrix
What are the 3 main categories of cell junctions?
- tight junctions
- desmosomes
- gap junctions
What type of proteins make up tight junctions?
Transmembrane cell-adhesion proteins
Describe tight junctions
Completely encircled near the apical surface
No intercellular space
NO GAPS
Used to keep stuff out (or selectively force stuff to go certain places)
“zippers”
What makes up gap (communicating) junctions?
Connexons
Describe gap junctions
Six transmembrane proteins arranged around a pore
Ions, nutrients, and other small solutes can pass between cells
Where are tight junctions found?
Digestive tract - the stomach is very acidic
Where are gap junctions found?
Cardiac and smooth muscle, embryonic tissue, lens and cornea
Describe desmosomes
Patch that holds cells together Not continuous Resist mechanical stress Hook-like, J-shaped proteins Anchor cytoskeleton to protein plaque, joined by cell adhesion proteins "snaps"
What are hemidesmosomes?
Half desmosomes
Anchor basal cells to basement membrane
What is the difference between a secretion and an excretion?
Secretion: products useful in body
Excretion: waste products
What are the two classifications of glands?
- exocrine
2. endocrine
How do exocrine glands make contact with the surface of the epithelium?
Ducts (surfaces can be external or internal)
How do endocrine glands make contact with surface of the epithelium?
They don’t, they secrete their products directly into the blood stream
What are hormones? Which type of gland secretes them?
Chemical messengers that stimulate cells elsewhere in the body
Secreted by endocrine glands
What are unicellular glands?
Found in predominantly non-secretory epithelium
Exocrine or endocrine
Ex: goblet cells in the trachea, endocrine cells of digestion
What is the purpose of the capsule in exocrine gland structure?
Connective tissue covering
Extensions ar ether capsule: septa/trabeculae (divide interior of glad into compartments/lobes)
What is the purpose of the stroma in exocrine gland structure?
Connective tissue framework
Includes blood vessels, nerves, etc
Supports/organized glandular tissues
What is the purpose of the parenchyma in exocrine gland structure?
Cells of synthesis and secretion
Typically cuboidal or simple columnar epithelium
What are the two classifications of glands based on duct shape?
- simple (unbranched)
2. compound (branched)
What are the 3 shapes of glands
- Tubular: narrow secretary portion
- Acinar: secretory cells form dilated sac
- Tubuloacinar: both tubular and acinar portions
What are the 3 types of glands based on type of secretions
- serous glands
- mucous glands
- Mixed glands
What do serous glands secrete?
Thin, watery fluids
Ex: perspiration, tears
High enzymatic content (digestive juices)
What do mucous glands secrete?
Glycoprotien (mucin)
Mucin absorbs water, sells, and forms mucous
What is an example of a mixed gland?
Salivary glands
What are the three types of glands based on release of the secretion?
- Merocrine (eccrine)
- Apocrine
- Holocrine
How do merocrine/eccrine glands work?
Exocytosis
The vesicles travel to the surface and release to exterior
Looks like it’s spraying out
(most exocrine glands are eccrine glands)
Ex: tear glands, pancreases, mammary glands
How do apocrine glands work?
Packages are produces in the cytosol (covered by membrane)
The packages are pushed to the surface of the cells and a droplet buds off cell surface
Ex: milk fat in mammary glands
How do holocrine glands work?
The gland secretes itself
Ex: oil gland of scalp and eyelid
What specific membranes are made of only connective tissue?
dura mater, synovial membranes, periosteum
What specific membranes are made of only epithelium?
anterooms surfaces of cornea, lens of eye
What is the largest membrane?
Cutaneous
What is the purpose of mucous membranes?
Line passageways
Absorptive, secretory, and protective
Ex: digestive, urinary, reproductive
How many layers make up mucous membranes?
2-3:
Epithelium
Lamina propria (overlying CT - areolar)
Muscular mucosae (smooth muscle)
What is the purpose of serous membranes?
Line thoracic and abdominopelvic cavities; internal organs
Reduces friction
What are serous membranes made of?
Simple squamous epithelium
Thin layer of areolar tissue
What is another word for internal organs?
Viscera
What divides the thoracic and abdominopelvic cavities?
Diaphragm
What is the outermost layer of a serous membrane called? Innermost layer?
Outermost - parietal serous membrane
Innermost - visceral serous membrane
What are the 3 portions of the thoracic cavity?
right, left, and medial
What makes up the medial thoracic cavity?
Mediastinum (heart, thymus gland, trachea, esophagus, etc)
What is the pericardium?
serous membrane that lines the heart
What makes up the right/left thoracic cavity?
lungs
Lungs are surrounded by _______
visceral pleura
Abdominopelvic cavity: what is included in the superior (abdominal) cavity?
Stomach, liver, spleen, gallbladder, most intestines
Abdominopelvic cavity: what is included in the inferior (pelvic) cavity?
Rectum, urinary bladder, reproductive organs, large intestine
What is the peritoneum?
Lines the abdominopelvic cavity Parietal - lines cavities Visceral - lines organs Retroperitoneal - behind peritoneum Intraperitoneal - inside peritoneum
Whats the difference in the cranial cavity and vertebral canal?
Cranial cavity - cranium/skull and brain
Vertebral canal - vertebrae and spinal cord
What are the meninges?
Membranous layers that line the cranial and vertebral cavities
Contains cerebrospinal fluid for nourishment
Not serous fluids
What are endothelium membranes made of and what do they do?
Made of simple squamous epithelium, lines the circulatory system
What do synovial membranes do and what are they made of?
Made of only connective tissue, line freely movable joints
Synovial fluid makes the joints slippery for smooth movement
