A&P Final Review

Axial skeleton

Central, supporting axis consisting of a total of 80 bones.

Appendicular skeleton

Bones of the limbs, pelvic, and shoulder areas totaling 126 bones.

Temporal bone

Located on the side of the cranium.

Bone Functions

Shape, support, protection, movement, electrolyte balance, blood production.

Blood Production

Occurs in bone marrow, producing blood cells.

Osteon

Basic structural unit of compact bone.

Bone Marrow

Red marrow produces blood cells; yellow marrow stores fat.

Epiphyseal Plate

Growth plate in children; site of bone growth.

Osteoblasts

Bone-forming cells that secrete bone matrix.

Osteoclasts

Cells that dissolve unwanted bone.

Endocrine System

Secretes hormones to communicate with cells.

Nervous System

Uses electrical signals for rapid communication.

Central Nervous System (CNS)

Consists of brain and spinal cord.

Schwann Cells

Form myelin sheath in the PNS.

Myelin Sheath

Insulates axons for faster electrical impulse transmission.

Nodes of Ranvier

Gaps in the myelin sheath at intervals.

Neurilemma

Outer layer of Schwann cells; aids nerve regeneration.

Macrophages

Clean up debris after nerve degeneration.

Afferent (sensory) neurons

Detect sensations and relay to the CNS.

Efferent (motor) neurons

Relay messages from brain to muscles.

Impulse conduction

Caused by electrical currents in neurons.

Membrane potential

Ions separated by a membrane create potential.

Depolarization

Na+ enters cell, changing interior to positive.

Action potential

Neuron becomes active, conducting impulse along axon.

Refractory period

Membrane polarized; Na+ and K+ misplaced.

Myelinated fibers

Increase speed of impulse conduction in neurons.

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

Excitation

process in which nerve action potentials lead to muscle action potentials; nerve impulse continues

Inhibition

process in which nerve action potential stops

Gray matter

Missing myelin; contains only cell bodies

Dorsal column

Sensations of deep pressure, vibrations

Somatic reflexes

involuntary stimuli transmitted to skeletal muscles from neural arcs in the spinal cord; keep the body from

Cerebrum

the largest portion of the brain

Gyri

thick ridges found in the brain

Sulci

divide up the gyri

Cerebellum

second largest region of the brain; contains more neurons than the rest of the brain

Brainstem

contains three structures: Midbrain, Pons, Medulla Oblongata

Longitudinal Fissure

divides the right and left halves of the cerebral hemispheres

Corpus Callosum

a thick bundle of nerves that connects the left and right hemispheres

Cortex

is specifically gray matter that covers the cerebrum and cerebellum

Ventricles (brain)

canals in the brain that contain cerebrospinal fluid

Cerebrospinal Fluid

Fluid that circulates around the brain and spinal cord.

Blood Brain barrier

Restricts what substances can pass from the bloodstream into the brain.

Midbrain

Relays sensory and motor impulses and is integral to auditory and visual reflexes.

Pons

Responds to signals from different parts of the brain and has attachments for several cranial nerves.

Medulla Oblongata

Attaches the brain to the spinal cord and controls the cardiac center and respiratory centers.

Diencephalon

Contains the thalamus and hypothalamus, which control sensory impulses and autonomic functions.

Thalamus

Gateway for every sensory impulse, transmitting to the cerebral cortex.

Hypothalamus

Controls the autonomic nervous system and influences the endocrine system.

Frontal lobe

Controls voluntary movements, memory, social judgment, decision making, reasoning, and aggression.

Temporal lobe

Controls hearing, smell, learning, memory, emotional behavior, and visual recognition.

Occipital Lobe

Concerned with analyzing and interpreting visual information.

Parietal lobe

Receives and interprets body sensations such as touch, temperature, pressure, and pain.

Insula

Plays a role in perception of pain, basic emotions, addiction, motor control, and self-awareness.

White matter

Bundles of myelinated fibers called tracts that carry impulses from one part to another.

Cerebral Cortex

Surface of the cerebrum, a thin layer of gray matter.

Basal Nuclei or Ganglia

Masses of gray matter found deep in the cerebrum that help in the control of movement.

Limbic System

The 'emotional brain' that is the seat of emotion and learning.

Hippocampus

Converts short-term memory into long-term memory.

Amygdala

Stores and can recall emotion, controlling emotions of anger, jealousy, and fear.

Somatic Association Area

concerned with determining the location and intensity of the sensory messages

Motor Association Area

Determines which movement is required for a particular task before movement begins.

Hormone Classifications

Derived from cholesterol, pass easily through a cell, bind to receptors in nucleus, synthesize new proteins, and alter the metabolism of the cell.

Pituitary Gland

Master Gland; Exerts more influence on body processes

Posterior Pituitary

Stores hormones produced by the Hypothalamus.

Growth hormone (GH)

Promotes protein synthesis, lipid and carbohydrate metabolism, and bone and skeletal muscle growth.

Negative Feedback

A systems response that reduces the processes leading to the output to bring stability back.

Homeostasis

process by which organisms maintain a relatively stable internal environment

Glucocorticoids

Cortisol; helps the body adapt to stress, repair damaged tissue, and maintain normal blood pressure.

Sex steroids

Include Estrogen, Progesterone, Testosterone, and Dihydrotestosterone (DHT).

Cortisol

Designed to give the body a burst of energy, increases heart rate, blood pressure, and elevated blood glucose.

Pineal Gland

Primarily responsible for secreting Melatonin and may regulate the timing of puberty.

Thymus

Produces the hormones: Thymosin and Thymulin

Thymosin

Crucial for the development and maturing of T cells.

Thymulin

Helps in the development of specialized T cells.

Thyroid

The largest endocrine gland, consists of two large lobes connected by a narrow band of tissue called Isthmus.

Thyroid hormones

Responsible for the regulation of metabolism, growth, and development.

Calcitonin

Helps in the regulation of calcium levels in the body.

Parathyroid gland

Produces parathyroid hormone (PTH)

Parathyroid hormone (PTH)

works with Calcitonin to regulate calcium levels; maintain bone density, muscle function, and nerve signaling.

Pancreas

Produces several hormones necessary for the body, including Insulin, Glucagon, Somatostatin, and Gastrin.

Insulin

Lowers blood sugar levels by promoting glucose uptake from the bloodstream into cells.

Glucagon

Raises blood sugar by stimulating the liver to release stored sugar into the bloodstream.

Gastrin

Stimulates the stomach to produce Hydrochloric Acid and gastric motility.

Edema

Fluid accumulation in interstitial spaces, causing tissue swelling.

Electrolyte Balance

Are substances that break up into electrically charged particles called ions when dissolved in water. A balance is crucial for proper body functioning.

Sodium

Main electrolyte in extracellular fluid. Determines the volume of total body water. Influences how body water is distributed. Plays a key role in depolarization.

Sodium Regulation (Low)

water level too high; Aldosterone prompts renal tubules to reabsorb Na+. Antidiuretic hormone (ADH) is suppressed → kidneys secrete water

Sodium Regulation (High)

Water level too low; Antidiuretic hormone (ADH) causes kidneys to reabsorb water. ADH stimulates thirst

Hypernatremia

Indicates greater sodium than water; usually self-corrects by triggering thirst.

Hyponatremia

Results from excess body water lower than normal ; usually corrected by excretion of excess water.

Potassium

Chief cation of intracellular fluid;

works hand-in-hand with sodium;

crucial for proper nerve and muscle function.

Hypokalemia

Low levels of Potassium; may result from diuretics, vomiting, or chronic diarrhea; makes cells less excitable.

Hyperkalemia

High levels of Potassium; makes nerve and muscle cells irritable; imbalances can cause life-threatening cardiac arrhythmias.

Hypercalcemia

High levels of Calcium; may result from hyperparathyroidism, hypothyroidism, alkalosis; inhibits depolarization.

Hypocalcemia

Low levels of Calcium; may result from hypoparathyroidism, hyperthyroidism, acidosis, diarrhea; increases excitation of nerves and muscles.

Main cation of extracellular fluid

Sodium

pH of blood

Ranges from 7.35 to 7.45