Human Ear Anatomy, Function, and Neural Pathways

What is the first structure to vibrate to sound?

Tympanic membrane (eardrum)

Where are the vestibule and semicircular canals located?

Inner ear

What are the components of the external ear?

Pinna, external acoustic meatus

What are the components of the middle ear?

Tympanic membrane, hammer, anvil, stirrup, pharyngotympanic tube

What are the components of the inner ear?

Cochlea, vestibule, semicircular canals, auditory nerve

What do the external and middle ear mostly contain?

Air

What is the inner ear filled with?

Fluid

What is the function of the pinna?

Collects sound

What is the function of the tympanic membrane?

Vibrates

What is the function of the cochlea?

Hearing organ

What is the function of the hammer, anvil, and stirrup?

Amplify sound

What is the function of the external acoustic meatus?

Ear canal

What is the function of the pharyngotympanic tube?

Equalizes pressure

What is the function of the semicircular canals?

Balance

What does the auditory nerve do?

Carries signals to brain

What is the path of sound?

Pinna → external acoustic meatus → tympanic membrane → hammer → anvil → stirrup → cochlea → cochlear nerve

Where is earwax produced?

External acoustic meatus by ceruminous glands

How long do olfactory cells live?

1-2 months

How long do gustatory (taste) cells live?

About 10 days

What are the five tastes?

Sweet, salty, sour, bitter, umami

What is anosmia?

Loss of smell

What do chemoreceptors detect?

Chemicals

What do mechanoreceptors detect?

Texture/crunchiness

What do thermoreceptors detect?

Temperature

What do nociceptors detect?

Spicy/painful sensations

What is the role of repetition, sleep, emotion, and attention in memory?

Help move memories to long-term memory

What is the function of dendrites?

Receives signals

What is the function of the cell body?

Control center

What is the function of the axon?

Carries impulse away

What is the function of the axon hillock?

Starts impulse

What is the function of the myelin sheath?

Insulation

What are nodes of Ranvier?

Gaps helping fast transmission

What is the synaptic cleft?

Gap between neurons

What do neurotransmitters do?

Carry messages

What is the sequence of a nerve impulse?

Resting state → threshold reached → sodium enters (depolarization) → potassium leaves (repolarization) → refractory period

What is the function of acetylcholine?

Muscle movement

What is the function of GABA?

Calming/inhibitory

What is the function of dopamine?

Reward/movement

What is the function of glutamate?

Excitatory/learning

What is the function of endorphins?

Pain relief

What do astrocytes do?

Support neurons and maintain environment

What do Schwann cells provide?

PNS myelin

What do oligodendrocytes provide?

CNS myelin

What does the myelin sheath do?

Speeds up impulses

What is the difference between the sympathetic and parasympathetic nervous systems?

Sympathetic = active/stress; Parasympathetic = resting

What does the CNS consist of?

Brain and spinal cord

What does the PNS consist of?

Nerves outside CNS

What is the function of afferent nerves?

Sensory to CNS

What is the function of efferent nerves?

Motor away from CNS

What is the function of somatic nerves?

Voluntary

What is the function of autonomic nerves?

Involuntary

What does the limbic system control?

Emotions/memory

What does the reticular formation control?

Alertness/consciousness

What are the parts of the brain?

Frontal, parietal, temporal, occipital lobes, cerebellum, pons, medulla oblongata, corpus callosum

What is the function of the frontal lobe?

Thinking/movement

What is the function of the parietal lobe?

Touch

What is the function of the temporal lobe?

Hearing/memory

What is the function of the occipital lobe?

Vision

What is the function of the cerebellum?

Balance/coordination

What is the function of the pons?

Breathing relay

What is the function of the medulla?

Heartbeat/breathing

What does the corpus callosum do?

Connects hemispheres

What are the meninges?

Dura mater → arachnoid mater → pia mater

What is syncope?

Fainting

What is a concussion?

Mild brain injury

What is a contusion?

Bruise

What is swelling in the brain?

Pressure buildup

What is a hemorrhage?

Bleeding in brain

What is the normal blood pH?

About 7.35-7.45, slightly alkaline

What are the four parts of blood?

Plasma, RBCs, WBCs, platelets

What is the universal donor blood type?

O negative

What is the universal recipient blood type?

AB positive

What does hemoglobin do?

Carries oxygen

What are the types of leukocytes?

Neutrophils, lymphocytes, monocytes, eosinophils, basophils

What is the function of neutrophils?

Bacteria fighters

What is the function of lymphocytes?

Immune response

What do monocytes become?

Macrophages

What is the function of eosinophils?

Parasites/allergies

What is the function of basophils?

Inflammation/histamine

Where is blood made?

Red bone marrow

What are the functions of blood?

Transport, protection, regulation

What is leukemia?

Cancer of WBCs

What is anemia?

Low RBCs/hemoglobin

What does the SA node do?

Pacemaker in right atrium; starts heartbeat

What does the AV node do?

Delays signal about 0.1 sec

What does the P wave represent?

Atria contract

What does the QRS complex represent?

Ventricles contract

What does the T wave represent?

Ventricles relax

What causes heart sounds?

Valves closing

What is the path of blood through the heart?

Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary arteries → lungs → pulmonary veins → left atrium → bicuspid/mitral valve → left ventricle → aortic valve → aorta → body → vena cava → right atrium

What is hypertension?

High BP (140/90+)