Anatomy and Physiology Comp 1 (Fall 2026)

Last Updated 8/19

The dorsal cavity houses the

brain and spinal cord (cranial cavity and vertebral canal)

The thoracic cavity houses the

right and left pleural (lungs) and mediastinum (heart)

The abdominopelvic cavity houses the

peritoneal cavity (membrane that lines the abdominal wall and pelvis // wraps around internal organs)

How many chromosomes do humans have?

46

The Plasmalemma is the

exterior membrane of the cell (phospholipid bilayer)

Plasmalemma function

• physical isolation

• sensitivity

• structural support

• regulation of exchange with the environment (permeability)

Examples of passive processes

diffusion, osmosis, facilitative diffusion

Examples of active processes

active transport, endocytosis, exocytosis

Diffusion

molecular movement of solutes; direction determined by relative concentrations

Osmosis

movement of water molecules toward high solute concentrations; requires membrane

Facilitated Diffusion

carrier molecules transport materials down a concentration gradient; requires membrane

active transport

carrier molecules work despite opposing concentration gradients

Endocytosis

formation of membranous vesicles (endosomes) containing fluid or solids at the plasmalemma

*specialized cells use this to engulf and destroy pathogens

Exocytosis

fusion of vesicles containing fluids and or solids with the plasmalemma

What can diffuse across the plasmalemma?

lipids, lipid soluble molecules, and soluble gasses (O2 and CO2)

*lipid soluble example: some hormones, cholesterol

What goes through membrane channels on the plasmalemma?

Water, small water soluble molecules and ions

What needs a carrier mechanism to go through the plasmalemma?

large molecules

Cytoplasm

• general term for material inside cell (including cytosol and organelles

• high amount of protein (15% - 30% of cell weight)

Cytosol

• mainly water, with high concentration of K+

• contains dissolved amino acids, lipids, carbs, and all organelles

Nonmembranous (hydrophilic) Organelles include

• cytoskeleton

• centrioles

• cilia

• flagella

• ribosomes

Cytoskeleton

internal protein that gives cytoplasm strength and flexibility

Four components:

• microfilaments

• intermediate filaments

• thick filaments

• microtubules

Microfilaments (actin)

• anchor cytoskeleton to integral proteins

• anchor plasmalemma to cytoplasm

• stabilize position of membrane proteins

Intermediate filaments (ex. keratin)

• provide strength

• stabilize organelle position

• transport material within the cytosol

Microtubules

• control cell chape

• aid in cell division and movement (centrioles, cilia, flagella)

Ribosomes

• nonmembranous organelles

• free ribosomes (free in cytoplasm)

• fixed ribosomes (attached to endoplasmic reticulum)

Membranous Organelles example

• mitochondria

• nucleus

• endoplasmic reticulum

• golgi apparatus

• lysosomes

• peroxisomes

Mitochondria

• double membrane

• atp production

Nucleus

• storage site of genetic material

• double membrane

Endoplasmic reticulum

network of intracellular membranes that form hollow tubes, sheets, and chambers (cisternae)

E. Reticulum functions to

• synthesize carbs, steroids, and lipids

• assemble and modify polypeptides

• storage

• transport molecules

• inactivate toxins

Golgi Apparatus

• synthesis and packaging of secretions

• packaging of special enzymes

• renewal of cell membrane

Functional link between ER and Golgi

GA matures proteins that come from ER to go to plasmalemma

Peroxisomes

• oxidases: break down compounds into hydrogen peroxide

• break down fatty acids

• neutralize toxins

Skeletal Muscle

• ER store calcium

• myosin and actin facilitate muscle contraction

Neuron structure

microtubules and filaments give dendritic termini shape

Sperm cell

structure for mobility; mitochondrial for atp

Intestinal epithelial cell

brush border increase cell surface area