In this live Anatomy & Physiology lecture, we explore the anatomy of the eye and connect each structure to its function, innervation, and clinical significance.

We begin with tear production and drainage before examining the extraocular muscles and the cranial nerves that control eye movement. We then travel through the eye’s major layers and structures—including the sclera, choroid, retina, cornea, lens, iris, ciliary body, and optic nerve.

Along the way, we discuss common conditions such as conjunctivitis, Sjögren syndrome, strabismus, amblyopia, myopia, astigmatism, retinal detachment, cataracts, glaucoma, macular degeneration, and red-green color blindness. We finish by following visual information from the rods and cones toward the optic nerve.

This episode is designed for beginning health-science and Anatomy & Physiology students. Because it was recorded during a live, model-based lecture, you may hear references to numbered anatomical structures and classroom questions.

Timestamps:

00:00 Tear production and lacrimal drainage
02:30 Conjunctivitis, dry eye, and Sjögren syndrome
05:00 Optic chiasm and visual fields
06:00 Extraocular muscles and eye movements
08:30 The trochlea and cranial nerves III, IV, and VI
10:30 Strabismus and amblyopia
12:00 Sclera, myopia, and astigmatism
14:20 Choroid, retinal nutrition, and diabetes
16:20 Retina, retinal detachment, and the cornea
18:00 Lens anatomy, cataracts, the macula, and the fovea
21:00 Accommodation and age-related changes in near vision
22:20 Optic nerve, optic disc, and the blind spot
22:50 Aqueous humor, drainage, and glaucoma
23:45 Vitreous humor and retinal support
25:20 Ciliary body, suspensory ligaments, and eye anatomy review
28:45 Ora serrata and the anterior edge of the retina
29:10 Pupil constriction, dilation, and autonomic control
30:40 The healthy retina and macular degeneration
31:50 Rods, cones, and color vision
32:50 X-linked red-green color blindness
33:40 From photoreceptors to the optic nerve

#AnatomyAndPhysiology #EyeAnatomy #Vision #HumanAnatomy #Physiology #HealthScienceStudents #NursingStudents #MedicalEducation #ScienceEducation #ScienceWithSusanna

Sympathetic vs. Parasympathetic Nervous System | Fight-or-Flight vs. Rest-and-Digest | Anatomy & Physiology

In this live Anatomy & Physiology lecture, we compare the sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) divisions of the autonomic nervous system. We walk through how these systems affect the heart, lungs, eyes, digestive tract, bladder, and blood vessels while connecting each physiological effect to the medications healthcare professionals commonly encounter.

You'll learn how norepinephrine, epinephrine, and acetylcholine produce their effects, how adrenergic and cholinergic receptors work, and why understanding receptor physiology makes it much easier to predict both the therapeutic effects and side effects of common medications.

Topics include beta blockers, albuterol, alpha-1 agonists and blockers, atropine, anticholinergic medications, EpiPens, anaphylaxis, asthma, COPD, bradycardia, urinary retention, and many of the clinical concepts encountered in nursing and allied health programs.

Timestamps

00:00 – Introduction: Sympathetic vs. parasympathetic nervous system
00:45 – Fight-or-flight effects on heart rate, blood pressure, and breathing
01:25 – Beta-1 adrenergic receptors and beta blockers (metoprolol)
03:55 – Beta-2 adrenergic receptors, bronchodilation, and albuterol
05:40 – Alpha-1 receptors and blood vessel constriction
07:10 – Norepinephrine vs. epinephrine: neurotransmitter vs. hormone
08:15 – Anaphylaxis, EpiPens, and epinephrine
09:20 – Sympathetic effects on pupils, saliva, tears, skin, and skeletal muscle blood flow
10:45 – Common side effects of beta blockers, beta-2 agonists, and alpha-1 blockers
12:35 – Memory tips for beta-1, beta-2, and alpha-1 receptors
13:10 – Parasympathetic nervous system: acetylcholine and muscarinic receptors
14:00 – Pupil constriction and eye drops (phenylephrine vs. anticholinergics)
15:00 – Rest-and-digest effects on the heart and digestive system
16:10 – Bladder contraction, urinary retention, and UTIs
17:20 – Common anticholinergic medications: motion sickness, Parkinson's disease, overactive bladder, COPD, and atropine
19:10 – Using atropine to treat symptomatic bradycardia
20:00 – Mechanism of action: understanding autonomic medications
21:00 – Side effects of anticholinergic drugs: dry mouth, constipation, urinary retention, blurred vision, tachycardia, decreased sweating, heat intolerance, and confusion
23:15 – Lecture summary

This lecture is designed for students in Anatomy & Physiology, Nursing, Dental Hygiene, Physical Therapist Assistant (PTA), Occupational Therapy Assistant (OTA), Diagnostic Imaging, and other health science programs.

#AnatomyAndPhysiology #AutonomicNervousSystem #Sympathetic #Parasympathetic #FightOrFlight #RestAndDigest #BetaBlockers #Albuterol #Atropine #Anticholinergics #NursingSchool #HealthcareStudents

Reflexes, Dermatomes, and Cranial Nerves | Anatomy & Physiology Lecture

Welcome to Science with Susanna! In this Anatomy & Physiology lecture, we explore how the nervous system protects the body through reflexes and how healthcare professionals use neurological examinations to assess brain, spinal cord, and cranial nerve function.

We'll discuss common reflexes, dermatomes, shingles, and all twelve cranial nerves, focusing on the simple clinical assessments that students will encounter in nursing, dental hygiene, physical therapist assistant (PTA), occupational therapy assistant (OTA), diagnostic imaging, and other allied health programs.

Rather than simply memorizing names, this lecture emphasizes what each cranial nerve does, how to test it, and what abnormal findings can reveal about neurological health.

• Purpose and importance of reflexes

• Protective reflexes

• Blood pressure reflexes

• Orthostatic hypotension

• Withdrawal reflex

• Crossed extensor reflex

• Patellar tendon reflex

• Achilles tendon reflex

• Babinski reflex

• Upper motor neuron maturation

• Positive Babinski sign

• Spinal nerve plexuses:

  • Cervical plexus

  • Brachial plexus

  • Lumbar plexus

  • Sacral plexus

• Phrenic nerve and breathing

• Sciatic nerve

• Dermatomes

• Shingles (Herpes zoster)

• Varicella-zoster virus reactivation

• Clinical recognition of shingles

• Complete overview of Cranial Nerves I–XII

• Bedside neurological assessments

• Eye movement examinations

• Pupillary light reflex

• Facial sensation and mastication

• Bell's palsy

• Hearing and balance

• Vertigo

• Aminoglycoside (gentamicin) ototoxicity

• Swallowing assessments

• Vagus nerve and parasympathetic function

• Shoulder shrug and tongue movement testing

• High-yield cranial nerve review

00:00 Introduction to reflexes

01:00 Withdrawal reflex and crossed extensor reflex

02:10 Patellar and Achilles tendon reflexes

03:10 Babinski reflex

05:00 Spinal nerve plexuses

06:20 Dermatomes and shingles

08:20 Introduction to the twelve cranial nerves

09:20 CN I–IV: Smell, vision, and eye movements

10:15 CN III, IV, and VI mnemonic (LR6, SO4, all the rest III)

12:00 Neurological eye examinations and pupillary light reflex

13:30 CN V: Trigeminal nerve

15:30 CN VII: Facial nerve and Bell's palsy

18:00 CN VIII: Vestibulocochlear nerve, hearing, balance, and vertigo

20:30 CN IX and X: Swallowing, taste, and the vagus nerve

24:15 CN XI and XII: Accessory and hypoglossal nerves

25:20 Comprehensive cranial nerve function review

Perfect for:

• Anatomy & Physiology students

• Nursing students

• Physical Therapist Assistant (PTA) students

• Occupational Therapy Assistant (OTA) students

• Dental hygiene students

• Diagnostic imaging students

• Anyone preparing for healthcare coursework or board examinations

Subscribe to Science with Susanna for clear, clinically relevant Anatomy & Physiology lessons that connect foundational science to real patient care.

#Anatomy #Physiology #CranialNerves #Neurology #Reflexes #NursingSchool #MedicalEducation #PTA #OTA #AlliedHealth #ScienceWithSusanna

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Spinal Cord and How the Brain Controls Movement | Anatomy & Physiology Lecture

Welcome to Science with Susanna! In this Anatomy & Physiology lecture, we explore how the spinal cord serves as the communication highway between the brain and the body. You'll learn how sensory information travels to the brain, how motor commands travel back to skeletal muscles, and how the brain coordinates smooth, purposeful movement.

We'll also examine the protective structures surrounding the spinal cord, including the meninges and cerebrospinal fluid (CSF), before discussing clinically important topics such as epidural anesthesia, shingles, hydrocephalus, spinal cord anatomy, and different types of intracranial bleeding.

Designed for beginning healthcare students, this lecture emphasizes understanding rather than memorization, helping you connect anatomy with the clinical situations you'll encounter in nursing, dental hygiene, PTA, OTA, diagnostic imaging, and other allied health programs.

• Cross-sectional anatomy of the spinal cord

• Vertebrae and the vertebral canal

• Epidural space and epidural anesthesia

• The spinal meninges:

  • Dura mater

  • Arachnoid mater

  • Pia mater

• Gray matter vs. white matter

• Posterior horn (sensory input)

• Anterior horn (motor output)

• Lateral horn and sympathetic nervous system

• Ascending and descending spinal tracts

• Dorsal root ganglion (DRG)

• Sensory neuron regeneration

• Nerve healing after injury

• Shingles and postherpetic neuralgia

• Cervical and lumbar enlargements

• Conus medullaris

• Cauda equina

• Filum terminale

• Hydrocephalus and ventricular shunts

• Epidural hematoma

• Subdural hematoma

• Subarachnoid hemorrhage

• Intracerebral hemorrhage

• Upper motor neurons vs. lower motor neurons

• Basal ganglia and cerebellum in motor control

00:00 Introduction to spinal cord anatomy

01:00 Epidural space and spinal meninges

02:20 Gray matter, white matter, and spinal cord organization

05:15 Dorsal root ganglion and sensory neurons

07:20 Spinal cord anatomy review

11:30 Nerve regeneration, shingles, and postherpetic neuralgia

13:45 Gross anatomy of the spinal cord

16:45 Cervical enlargement, lumbar enlargement, cauda equina, and conus medullaris

17:30 Hydrocephalus and CSF shunts

19:00 Intracranial bleeding:

• Epidural hematoma

• Subdural hematoma

• Subarachnoid hemorrhage

• Intracerebral hemorrhage

21:20 Upper motor neurons vs. lower motor neurons

22:30 Cerebellum, basal ganglia, and coordinated movement

Perfect for:

• Anatomy & Physiology students

• Nursing students

• Physical Therapist Assistant (PTA) students

• Occupational Therapy Assistant (OTA) students

• Dental hygiene students

• Diagnostic imaging students

• Anyone learning neuroanatomy for the first time

Subscribe to Science with Susanna for clear, clinically relevant Anatomy & Physiology lessons that make complex topics easier to understand.

#Anatomy #Physiology #Neuroanatomy #SpinalCord #NursingSchool #MedicalEducation #PTA #OTA #AlliedHealth #ScienceWithSusanna

In this episodeApproximate chapter timestamps

CSF Circulation and Meninges | Anatomy & Physiology Lecture

Welcome to Science with Susanna! In this college-level Anatomy & Physiology lecture, we explore how cerebrospinal fluid (CSF) protects and supports the central nervous system while following its complete pathway through the brain and spinal cord. We also introduce the meninges and connect these structures to important clinical conditions that healthcare students will encounter in nursing, dental hygiene, physical therapist assistant (PTA), occupational therapy assistant (OTA), diagnostic imaging, and other allied health programs.

Rather than memorizing isolated facts, this lecture emphasizes the "why" behind the anatomy so you can build a deeper understanding of how the nervous system functions.

• Functions of cerebrospinal fluid (CSF)

• Brain buoyancy and protection

• Nutrition and immune communication within the CNS

• Ventricles of the brain

• Choroid plexus and CSF production

• Ependymal cells and CSF circulation

• CSF flow pathway:

  • Lateral ventricles

  • Interventricular foramina

  • Third ventricle

  • Cerebral aqueduct

  • Fourth ventricle

  • Median and lateral apertures

  • Central canal

  • Subarachnoid space

  • Arachnoid villi

  • Superior sagittal sinus

• Hydrocephalus and CSF shunts

• The meninges:

  • Dura mater

  • Arachnoid mater

  • Pia mater

• Falx cerebri and separation of the cerebral hemispheres

• Epidural anesthesia and post-dural puncture headache

• Clinical relevance of CSF circulation

• Bonus discussion: split-brain research and brain lateralization

00:00 Introduction to cerebrospinal fluid

02:40 The ventricles and choroid plexus

05:20 CSF exits the fourth ventricle

06:20 Step-by-step CSF flow review

08:45 CSF circulation around the brain

10:00 Arachnoid villi and return to the bloodstream

11:45 CSF labeling practice

18:30 Introduction to the meninges

22:00 Superior sagittal sinus and falx cerebri

23:45 Split-brain experiments and lateralization

29:00 Meninges review and labeling exercise

31:00 Epidural anesthesia and clinical applications

Who is this for?

• Anatomy & Physiology students

• Nursing students

• PTA and OTA students

• Dental hygiene students

• Diagnostic imaging students

• Anyone interested in understanding human anatomy

If you enjoy learning anatomy through simple explanations, clinical examples, and memorable stories, subscribe so you don't miss future episodes from Science with Susanna.

#Anatomy #Physiology #Neuroscience #NursingSchool #Premed #MedicalEducation #AlliedHealth #CSF #Brain #Meninges #ScienceWithSusanna

In this episodeApproximate chapter timestamps

Practice Blood Flow Through the Heart with me!