Term 1 Revision - Human Biosciences 2 - PDF

Official Open Te r m 1 Revision H u m a n B i o s c i e n c e 2 D o n ’ t f o r g e t t o p r a c t i c e Wo r k s h e e t s & P o s t - L e c t u r e Q u i z z e s ! HBS12@Ngee Ann Polyte...

Official Open Te r m 1 Revision H u m a n B i o s c i e n c e 2 D o n ’ t f o r g e t t o p r a c t i c e Wo r k s h e e t s & P o s t - L e c t u r e Q u i z z e s ! HBS12@Ngee Ann Polytechnic Oct2024  Official Open This is not Common Test Revision. Students are required to revise this also for Exam. Lecture and McGraw Hill Textbooks (2 x eBooks) are for reading & understanding on concepts of the topics. Don’t your waste time by memorising each & every slides. Practice more on ….. Post-Lecture Summary slides Worksheets Quizzes for practical class HBS12@Ngee Ann Polytechnic Oct2024 2 Official (Closed) - Non Sensitive Structure & Function of NEURON Dendrites Receive signals (Axon terminal) Contains the Cell body nucleus and Building blocks of organelles Carry signals to nervous Neuron Transmits nerve Axon system the next impulse cell Insulates axon, Protects, supports increases speed of Neuroglia Myelin sheet and regulates transmission environment Bulb-shaped Axon terminals endings that form a synapse with the HBS12@Ngee Ann Polytechnic Oct2024 next cell  Most common in the CNS and efferent neurons Multipolar Neuron Have two or more dendrites and one axon Found in the sensory Neuro Classified based Unipolar division on the /psudounipol structure ar neuron Only one process emerging Classified based from the cell. on its n function found in special sensory, olfactory epithelium and Bipolar neuron retina. Two processes extend from the cell body, One is the and one the axon dendrite. HBS12@Ngee Ann Polytechnic Oct2024  a. Sensory neuron Receive informatio Sensory n from b. Interneuron neuron sensory receptors Neuro Connects sensory and Classified motor based on its Interneuron c. Motor neuron function neurons and process n information Carry Motor / information to efferent peripheral neuron targets called effectors HBS12@Ngee Ann Polytechnic Oct2024  Astrocyt Support the blood- brain barrier es Building blocks of nervous Ependymal Cerebrospinal fluid (CSF) production cells CN S Defence against Neuro Microgli invading pathogens. n a (Increased in CNS infection) Protects, supports Produce myelin in Neurogl Oligodendrocy and regulates CNS ia environment tes system Surround and Satellite support neuron cells cell bodies PN S Schwann Produce myelin in cells PNS HBS12@Ngee Ann Polytechnic Oct2024  Information Official (Closed) - Non Sensitive of transmission in a neuron Sodium channels close, voltage- gated potassium channels open, and potassium ions move out of the cell. Repolarization begins. When a neuron is stimulated, an +30 3 electrical impulse is generated and D E P O L A R I Z AT I O N R E P O L A R I Z AT I O N conducted along 0 the length of its Membrane potential (mV) axon. Resting 2 This process, potential Voltage-gated sodium Potassium channels called action –40 close, and both sodium channels open and potential and potassium chan- sodium ions move into –60 Threshold the cell. The membrane nels return to their normal states. 1 potential rises to +30 –70 mV. A graded 4 depolarization brings Propertie Electrolyte an area of excitable s of s (Na+, membrane to thresh- plasma K+, old (–60 mV). REFRACTORY PERIOD membran Cl-) During the refractory period, e and the membrane cannot protein respond to further stimulation. s HBS12@Ngee Ann Polytechnic Oct2024 0 Time (msec) 1 2 HBS12@Ngee Ann Polytechnic Oct2024 8 How Action Potential transmitted across cholinerg An action potential arrives presynaptic ACh binds to receptors and depolarizes neuron and the postsynaptic membrane. Na channels depolarizes the axon terminal activated & initiated AP if threshold is Presynaptic Action potential reached. neuron Synaptic EXTRACELLULAR vesicles FLUID Initiation of Axon action potential terminal if threshold is reached AChE POSTSYNAPTIC NEURON AP Propagated & depolarization of Extracellular Ca2+ enters the axon postsynaptic membrane ends as ACH is terminal, triggering the exocytosis/release broken down by an enzyme AChE of ACh (acetylcholinesterase) ACh Propagation of action potential (if generated) Ca2+ Ca2+ Synaptic cleft Chemically regulated sodium ion channels HBS12@Ngee Ann Polytechnic Oct2024  Paired cerebral Each hemisphere sends and hemispheres by the receives information from the longitudinal fissure opposite side of the body Gyri and sulci to iincrease surface area Frontal lobe: primary motor area and conscious thought, problem solving, behavior Parietal lobe: primary Lobes somatosensory Cerebrum Central nervous Temporal lobe: primary auditory, memory, and speech area system Brain Occipital lobe : primary visual area Spinal Cord The general interpretive area or Wernicke's area (temporal lobe), Integrative areas, usually comprehension only in the dominant hemisphere (left) The speech center or Broca's area (Frontal lobe) 10 Articulation HBS12@Ngee Ann Polytechnic Oct2024  Thalamus Regulates hunger, sleep, thirst, body Diencephalon temperature, and water balance. Hypothalamus Controls the pituitary gland; serves as a link between the nervous and Produces smooth, endocrine systems. coordinated, voluntary movements. Cerebellum Central nervous Brain Receives and integrates sensory input, maintain balance and coordination system Relay station for auditory and visual The midbrain information. Connects the cerebral cortex to the Brain stem The pons medulla and to the cerebellum Controls many vital autonomic Spinal Cord The medulla oblongata functions such as heart rate, breathing, and blood pressure HBS12@Ngee Ann Polytechnic Oct2024 11  Skull Bones Vertebral bones provides a supportive framework for the CN blood vessels and protect the CNS from mechanical Meninges damage. Dura Protections of CNS 3 layers Arachnoid Pia a protective fluid that bathes the Cerebrospinal fluid brain & spinal cord and fills the spaces. Regulate substance Blood brain barrier in blood gaining access to the brain ADD A FOOTER HBS12@Ngee Ann Polytechnic Oct2024 12  Case Discussion Mdm Koh is hospitalized for left-side cerebral stroke. She experienced sudden onset of weakness in her right upper and lower limbs. Why did left-side cerebral stroke cause right side weakness? The motor cortex of each cerebral hemisphere is mainly responsible for control of movements of the opposite (contralateral) side of the body. (motor & sensory tracts (in the brain nerve fibres are called tracts) crossed in the midline) What is stroke? What are the two types of stroke? Cerebrovascular accident (CVA) Due to lack of oxygen when the blood flow to the brain is lost by blockage (ischemic) or rupture of an artery to the brain (Hemorrhagic). HBS12@Ngee Ann Polytechnic Oct2024  Discussion Mdm Koh was unable to speak fluently but she was able to understand what was communicated to her. What medical term is used for this type of speech disorder? Broca’s aphasia/expressive aphasia/ difficulty in articulation Where is the affected Broca’s area located? Left frontal lobe (dominant hemisphere) Is she likely to be left-handed or right-handed? Stroke was on the left side. Her articulation of speech also affected. Broca’s area is on the dominant side, left hemisphere. Her motor control is on the opposite side & she is likely right-handed. HBS12@Ngee Ann Polytechnic Oct2024 Clinical Notes Meningitis Meningitis: Inflammation of the meningeal layers Mainly due to infections organisms in the cerebrospinal fluid CSF Diagnosed by obtaining CSF by lumbar puncture ( spinal tap) Spinal tap or lumbar puncture: special needle inserted into the arachnoid layer (under dural) and extracts CSF. Which level? Below L1-L2, mostly at L3-L4or L4-5. Spinal cord ends at L1- 2 and less risk of injuring spinal cord. ADD A FOOTER HBS12@Ngee Ann Polytechnic Oct2024 15 Clinical Notes Head injury & Intracranial haemorrhage Severe head injury may damage cerebral blood vessels Epidural haemorrhage: collection of blood between dura and the cranium, bleeding into tight layer so CT scan show rounder crescent shadow Subdural haemorrhage: collection of blood between the dura and arachnoid. Bleeding into loose layer, flat crescent shadow on CT. Subarachnoid Haemorrhage: Bleeding / extravasation of blood into the subarachnoid space 16 between the pia and arachnoid HBS12@Ngee Ann Polytechnic Oct2024 Clinical Notes Aphasia Language disorder that affects the ability to communicate. Wernicke's Aphasia (receptive): Lack of comprehension or understanding. Wernicke’s area is located at the temporal lobe of dominant hemisphere. Broca's Aphasia: Difficulty to articulate but understand. Broca’s area is located at the frontal lobe of dominant hemisphere. HBS12@Ngee Ann Polytechnic Oct2024 17  Central Sulcus: Separates frontal and parietal lobes Primary motor cortex: Control motor functions of the opposite side of the body Parietal lobe: Process sensory information Temporal lobe: Memory, sensory inputs Language comprehension (Wernicke area) Frontal lobe: Motor/ Broca’s area: motor control of speech  Broca’s aphasia movement And high-order functions such as cognition, reasoning, judgement, HBS12@Ngee Ann Polytechnic Oct2024 problem-solving etc.  Thalamus: Relay center for Sensory information Hypothalamus: Regulate body Temperature, control hormones Midbrain: Relays visual & sensory signals Pons: Links cerebellum with Occipital lobe: midbrain, Primary visual diencephalon & processing cortex cerebrum Medulla Oblongata: Cerebellum: Contains reflex Coordination & balance centers for regulating Control fine motor heartbeat, breathing movements HBS12@Ngee Ann Polytechnic Oct2024  Central Nervous System Brain and Spinal cord Information processing integrates, processes, and coordinates sensory input Cranial nerves: and motor commands. 12 pairs of nerves attached to the Peripheral brain. Nervous System The afferent division The efferent division carries motor commands brings information to the Referred to by Roman numerals CNS from the receptors. from the CNS to peripheral tissues and systems. and name. includes Some cranial nerves contain only sensory fibers, some only motor fibers; others are mixed. Somatic Autonomic Concerned with the head, neck, nervous system nervous system and facial regions. (The Vagus nerve (X), has branches to the neck and internal organs). Parasympathetic Sympathetic division division Spinal nerves: Receptors Effectors 31 pairs arise from the spinal Smooth cord. Somatic sensory Visceral sensory muscle receptors (monitor receptors (monitor Ganglia (singular, the outside world internal conditions Cardiac ganglion) and our position in it) and the status of muscle other organ systems) Skeletal Glands collections of nerve cell bodies muscle outside the CNS. Receptors are sensory structures that detect changes Effectors are target organs whose activities in the internal or external environment. change in response to neural commands. HBS12@Ngee Ann Polytechnic Oct2024  The olfactory nerves Sensory: sense of smell (CN I) Sensory: Carry visual The optic nerves (CN information from the II) retina (eyes) The Cranial Innervate four extrinsic eye muscles – eye Nerves movement The oculomotor Motor: nerves (CN III) control the size of the Motor: Innervate pupil The trochlear nerves superior oblique (CN IV) (extrinsic muscles of the eyes) Motor: muscles of mastication The trigeminal Mixed nerves (CN V) Sensory: over the face area The abducens Innervate lateral rectus nerves (extrinsic eye muscle) (CN VI) HBS12@Ngee Ann Polytechnic Oct2024  Sensory fibers: taste from anterior 2/3 of tongue The facial nerves Mixed nerve Motor fibers provide facial expressions (CN VII) Control lacrimal (tear) gland and salivary glands The vestibular nerve: balance and The position vestibulocochlea Sensory: r nerves (CN VIII) The Cranial The cochlear nerve: sense of hearing Nerves Sensory: taste on the posterior third of the tongue The BP and blood gases glossopharyngea Mixed nerves l nerves (CN IX) Motor: pharyngeal muscles used in swallowing Sensory input vital to autonomic control of the viscera The Vagus Motor control includes the soft palate, Mixed nerve nerves (CN X) pharynx, and esophagus Motor: shoulder The accessory muscles, move nerves (CN XI) shoulder The hypoglossal Tongue movement, move substances Motor: tongue around in the mouth, protrusion of nerves (CN XII) tongue  R CNIII defected: L pupil constricts when light on RE, so R CNII defected: No Normal: Both eyes R CNII is fine. L side responds response in both eyes constrict for both L&R to light & constricts. RE may when light shown to RE. light be down & out due to muscle weakness. Case Discussion HBS12@Ngee Ann Polytechnic Oct2024  Case Discussion When the patient was asked to look at the Abducent right side, both eyes nerve Palsy OK. When asked to look at the left side, RE LE left eye cannot move to the left, because lateral rectus cannot move X which is innervated by left abducent nerve. HBS12@Ngee Ann Polytechnic Oct2024  Case Discussion 1. What are the possible causes? Provisional diagnosis? Brain injury (stroke)? Cranial nerve palsy (Bell’s Palsy)? 2. What are other clinical features apart from facial muscle weakness? 3. Is prognosis good? Does he need surgery? 48-year-old woman Which side is abnormal? Complaint of left sided The side where muscles drop, skin facial weakness for 2 folds gone/less because no control by days HBS12@Ngee Ann Polytechnic Oct2024 nerve/brain  Provisional diagnosis Brain – opposite side which is right. Frontal lobe controls movement. So Right Frontal lobe injury. CN – same side, left. Facial muscle innervated by facial nerve. So Left Facial nerve palsy. Clinical features on the affected side Prognosis Drooping of face Facial nerve palsy or Bell’s Palsy is Dropping eye lid, cannot close common. properly Mostly idiopathic or caused by viral Abnormal tear secretion (due to CNVII infection of CNVII. itself & eye lid) Prognosis is good. Symptomatic Abnormal taste sensation treatment with corticosteroid. Unable to close lip Brain or upper motor neuron lesion Drooling of saliva (due to CN VII itself can easily be excluded by clinical HBS12@Ngee Ann Polytechnic Oct2024 & lip) features  An action Reflex A stimulus activates a potential Arc travels down sensory sensory receptor neuron Information processing occurs with the interneuron An action potential The effector travels down organ motor responds HBS12@Ngee Ann Polytechnic Oct2024 neuron  Pupillary reflex / Light reflex Patella reflex / knee jerk Light striking Sti mu lus retina Aff Optic nerve ere nt Ce Brain stem ntr e Oculomotor Eff ere nt Nerve Constriction of Res po nse pupil Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs HBS12@Ngee Ann Polytechnic Oct2024  Official Open Autonomic Nerve Pathways Sympathetic Nerves Parasympathetic Nerves Location of motor Thoracolumbar spinal Craniosacral; Cranial nerve fibers nerves, T1 to L2,3 (III, VII, IX, X) and sacral spinal nerves Neuron and ganglion Shorter preganglionic Long preganglionic nerves than post nerves than post ganglionic nerves. ganglionic nerves. Ganglions located Ganglions located near spinal cord near the target organs. Receptor at synapse Alpha 1, Alpha 2, Beta Muscarinic and 1 and Beta 2 nicotinic Neurotransmitter Norepinephrine Acetylcholine Type of control Involuntary Effectors Smooth muscles, Cardiac muscles and glands HBS12@Ngee Ann Polytechnic Oct2024 HBS12@Ngee Ann Polytechnic Oct2024 Case Discussion (Students can stand up & try it) 1. What are the sensory system structures involved to balance the body when you are standing on one leg? Balancing on one leg involves the coordinated efforts of several sensory systems that work together to help you stay upright and stable. These systems include: 2. Eyes: Eyes provide information about your surroundings and assist in maintaining your orientation. (Sensory – PNS) 2. Vestibular System: It is located in the inner ear and detects changes in head position and movement, which is crucial for balance. (Sensory – PNS) 3. Proprioceptors: These sensory receptors in the muscles and joints sense the position and movement of body parts. (Sensory – PNS) 4. Brain and Spinal Cord (CNS): They process the sensory HBS12@Ngee Ann Polytechnic Oct2024 information and coordinate the necessary motor responses  Case Discussion (Students can stand up & try it) 2. You would feel difficulty in balancing when you close your eyes while standing on one leg. Why? When you close your eyes while standing on one leg, you remove the visual input that helps you maintain balance. Without visual input, your brain has to depend more on the vestibular system (inner ear) and proprioceptive feedback (sensation from muscles and joints) to maintain balance. This increased reliance on other sensory systems can make it harder to stay balanced, especially if those systems are not as strong or well-coordinated as your visual system. HBS12@Ngee Ann Polytechnic Oct2024  Case Discussion (Students can stand up & try it) What about cerebellum? The sensory structures like, The vestibular system primarily detect changes in head position and movement. The visual system provides spatial orientation. The proprioceptors in muscles and joints sense body position and movement. These systems provide the necessary sensory input But the cerebellum integrates and processes this information to produce coordinated and balanced movements (Motor). HBS12@Ngee Ann Polytechnic Oct2024  Case Discussion A patient had stroke in left occipital lobe as shown in CT scan. Describe the neurological deficit that results from it. A stroke in the left occipital lobe causes the patient could not see anything to the right side of his midline in both eyes i.e., the right visual field loss in both eyes. It is known as Right Homonymous Hemianopia. Here’s why: Each eye sends visual information to both sides of the brain. The left side of the brain processes the right visual field from both eyes. When the left occipital lobe is damaged, the patient lose vision on the right side of both eyes. HBS12@Ngee Ann Polytechnic Oct2024  Continuation of skin The Eyelids Protects the surface of eye Rich in The accessory sebaceous glands Anatomy and Physiology of the Eye structures (Eyelids and associated exocrine glands) Structures associated with the The Lacrimal production, secretion, and removal of Apparatus tears The extrinsic eye Superior oblique, Inferior oblique, Superior Rectus, muscles Inferior Rectus, Medial Rectus, Lateral Rectus The eyeball HBS12@Ngee Ann Polytechnic Oct2024  Outer fibrous layer: Protects and Cornea Refracts light rays supports the eye Sclera controls the shape of the Ciliary body lens for focusing its dark pigment Lens Refracts and focuses light rays Middle layer: absorbs light that photoreceptors Choroid have not Iris Regulates light entrance absorbed Pupil Admits light The Eye Make black-and-white Rod cells vision possible Make color Cone cells Inner layer: Contains sensory vision possible receptors for Retina sight Makes acute Fovea centralis vision possible Transmits impulses to the Optic nerve visual cortex Nourishes the lens and maintains Anterior cavity Aqueous humor pressure within the eye holds the retina Posterior cavity Vitreous humor HBS12@Ngee Ann Polytechnic Oct2024 in place  Official Visual Open Pathways Nerve impulses are carried by the optic nerves from the eyes to the optic chiasma. After exiting the optic chiasma, the optic nerves continue as optic tracts. The two tracts from each eye, continue to left and right visual cortexes of the occipital lobes. Each eye controlled by both visual cortexes for left & right visual field respectively. HBS12@Ngee Ann Polytechnic Oct2024 Clinical Notes: Eye HBS12@Ngee Ann Polytechnic Oct2024 Cataract: Opacity of the lens Conjunctivitis: Irritation or damage to the conjunctiva Sty: infected sebaceous glands in the eyelid Glaucoma: Increased pressure inside the eyeball Retinal Detachment: Separation of the retina from the choroid layer. Diabetic retinopathy & Hypertensive Retinopathy: Important eye complication in common medical diseases in community. Patients with diabetes & hypertension requires yearly eye check.  Pinna External or Outer Ear lined with hairs and modified sweat glands that secrete earwax Auditory canal Guards against the entrance of foreign matter begins at the tympanic membrane (eardrum) and ends at a bony wall containing two small openings covered by Anatomy and Physiology of the Ear membranes. Three small bones found Middle Ear here-Ossicles Equalizes air pressure across Auditory tube (eustachian or pharyngotympanic tube): connects the the tympanic membrane, middle ear to the nasopharynx. Pharyngitis can spread to middle ear The vestibular nerve carries signals semicircular canals Rotational equilibrium generated here to the brain The vestibular nerve carries signals Inner Ear Vestibule Gravitational equilibrium generated here to the brain Nerve signals now begin in the cochlear Cochlea handles hearing nerve and travel to the auditory cortex in the temporal lobe and interpreted as a sound. HBS12@Ngee Ann Polytechnic Oct2024  Nociceptors - Respond to in pain Chemorecept chemical or stimulation Blood ph Photorecepto Respond to rs light Respond to Skin, Thermorecep Receptor temperature hypothalamu tors changes s Tactile touch receptors Mechanocept Baroreceptor pressure ors s Proprioceptor position s HBS12@Ngee Ann Polytechnic Oct2024  Case Discussion The condition is – goiter, enlargement of the thyroid gland. Goiter can occur with Hyperthyroidism (increased T3, T4), Hypothyroidism (decreased T3, T4) or Euthyroidism (normal range T3, T4). Laboratory Tests Hyperthyroidism – increased T3 & T4 and very low TSH. Hypothyroidism – decreased T3 & T4 and very high TSH. HBS12@Ngee Ann Polytechnic Oct2024 The pituitary gland Hormones Produced by the Anterior Pituitary: 1. Thyroid-stimulating hormone (TSH) 2. Adrenocorticotropic hormone (ACTH) 3. Follicle-stimulating hormone (FSH) 4. Luteinizing hormone (LH) 5. Prolactin (PRL) 6. Growth hormone (GH) 7. Melanocyte-stimulating hormone (MSH) Pituitary Hormones Produced by the Posterior Gland Pituitary: 8. Anti-diuretic hormone (ADH) 9. Oxytocin HBS12@Ngee Ann Polytechnic Oct2024  The adrenal cortex-discussion Adrenal cortex Glucocorticoid Mineralocorticoi s ds cortisol, corticosterone Aldosterone , and cortisone Regulate Active in the Suppress carbohydrate, causes the kidneys stress immunity (anti- protein, and fat to reabsorb Na+. response inflammatory) metabolism Raise the blood glucose Regulates blood pressure level HBS12@Ngee Ann Polytechnic Oct2024  Adrenal medulla-discussion er part  Adrenal medulla Adrenal ter part  Adrenal cortex medulla Epinephrin Norepineph e rine (Adrenaline (Noradrena ) line) bring about changes that occur during a short-term response to stress (flight or fight response) HBS12@Ngee Ann Polytechnic Oct2024  Endocrine pancreatic tissue is called pancreatic islets (islets of Langerhans) that contain a variety of cell types: A cells—secrete glucagon. B cells—secrete insulin. Pancreas  Discussion-endocrine pancreas Fasting Ingestion of food Blood sugar is low Blood sugar level increases Pancreas Pancreas Glucago n Insulin Blood sugar Blood sugar level increases level decreases HBS12@Ngee Ann Polytechnic Oct2024  Hormones regulating blood glucose Glucagon Insulin is the only hormone in the Growth hormone body that decreases the blood sugar levels. Glucocorticoids Epinephrine, Growth hormone & Norepinephrine glucocorticoid increases blood glucose during physiological stress. Blood Glucose levels Thus, deficiency of insulin will have a big impact as there are many Insulin other hormones to increase blood glucose. HBS12@Ngee Ann Polytechnic Oct2024  DISUCSSION: Parathyroid hormone is released when the blood calcium level is low, to increase the blood calcium level. Why Calcium is important? Bone formation is not the only function, there are other functions such as nervous system ( release of NT at synapse) and also muscle contraction. Calcitonin from thyroid gland is to lower the blood calcium level. Isn’t it better if calcium is high in blood? What conditions can be caused by high blood calcium, other than stone formation? Deposition on soft tissues such as blood vessels, heart valves etc. Parathyroid Glands HBS12@Ngee Ann Polytechnic Oct2024  Five General Functions of the Integument Protection Skin covers underlying tissues and prevents fluid loss, protects from UV radiation Temperature Skin regulates heat exchange with the maintenance environment Synthesis and Epidermis synthesizes vitamin D3 while dermis storage of stores lipids in adipose tissue nutrients Sensory Receptors for pain, pressure, touch, and reception temperature detect stimuli and send information to nervous system Excretion and Glands excrete salts, water, and organic wastes secretion while specialized mammary glands secrete milk HBS12@Ngee Ann Polytechnic Oct2024  Epidermis Contains skin pigmentation called melanin Melanin absorbs UV rays & protect the inner structures Also protect fluid loss Dermis Contains accessory structures of skin During tattooing, ink is injected into dermis Hypodermis Store fats Provide insulation Cushion the structures of the integument Subcutaneous injections are administered into this layer HBS12@Ngee Ann Polytechnic Oct2024  Hair follicle: Prevents entry of foreign particles into nose, eyes, and ears Sebaceous gland: Secretes sebum, lubricates hairs If ducts are blocked, leads to acne Arrector Pili Muscle When the body is cold, they contract all at once, causing the hair to stand up straight, trap air & insulate as a layer, prevent heat loss Sweat gland: Regulates body temperature, Excretion of metabolic waste products Nerve Receptors Touch receptors, Pressure receptors HBS12@Ngee Ann Polytechnic Oct2024 Vitamin D3 synthesis Exposure to sunlight (UVB) Cholesterol in epidermis Vitamin D3 (inactive form) Activated in Liver and Kidneys  Calcitriol (active vitamin D) Increased absorption of calcium in the intestine HBS12@Ngee Ann Polytechnic Oct2024  Why does exposure to sunlight darken skin? Exposure to sunlight (UVB) Stimulate melanocytes Production of Tanned skin / melanin darker skin absorbs ultraviolet (UV) radiation protecting deeper layers HBS12@Ngee Ann Polytechnic Oct2024  Skin Color Changes Role of dermal circulation Oxygenated blood is bright red resulting in a flushed, red skin color when dermal blood vessels dilation Short-term (minutes to hours) paling of the skin occurs with vasoconstriction Long-term (days & weeks) paling of the skin occurs with decreased RBC production or blood loss, more distinct on mucous membrane, mouth lips, conjunctiva etc) the condition is called anaemia. Cyanosis, a bluish coloration, occurs when blood oxygen supplies are diminished. Peripheral cyanosis at fingers & toes nails and more severe oxygen deprivation at lips & tongue, central cyanosis. Usually occurs with heart and lungs diseases or haemoglobin disorders. Jaundice, yellowish discoloration skin and mucous membrane. It is due to accumulation of bilirubin. Usually occurs in liver disease and massive RBC ruptures. Orange hue discoloration of the skin due to excessive intake of carotene does not require immediate medical attention. HBS12@Ngee Ann Polytechnic Oct2024  Melanocytes produce melanin, a pigment that colors the skin absorbs ultraviolet (UV) radiation protecting deeper layers Detrimental Effects of Sunlight on Skin Excessive sun exposure can cause burns to the skin and increase the risk of cancer over the long term. Beneficial Effects of Sunlight on Skin Adequate sun exposure is required for the synthesis of vitamin D in the skin. HBS12@Ngee Ann Polytechnic Oct2024  The Female Reproductive Tract Gonads Ovary Ducts Fallopian tube Uterus External HBS12@Ngee Ann Polytechnic Oct2024 genitalia  The Ovaries Female reproductive gland that produces eggs and female hormones The gametes or the eggs are called as ova Secretion of female sex hormones : Estrogens Progesterone HBS12@Ngee Ann Polytechnic Oct2024  HBS12@Ngee Ann Polytechnic Oct2024 The Uterine Wall – 3 layers Endometrium Has two layers: a functional layer that is shed during each menstrual period and a basal layer of reproducing cells. The functional layer varies in thickness according to a monthly cycle called the uterine cycle. Myometrium Muscle layer contracts during labor and delivery Oxytocin increase the uterine contractions. Perimetrium Outer serosa layer of the uterus  Anterior pituitary FS H LH Follicular phase Ovarian cycle Ovulation Menstrual cycle Ovar Luteal phase y Estrogen Progesterone Progestero Menstruation ne Proliferative Uterine cycle phase Maintain endometrium Secretory Endometrium growth phase HBS12@Ngee Ann Polytechnic Oct2024  Menstrual cycle (Don’t memorize, get the concept. It’s easy!) Luteal phase of ovarian cycle (Day 15 – 28) shedding of endometrium estrogen & progesterone, Menstruation: Day 1-5, low 5) Corpus luteum produces progesterone to maintain Endometrium. (So that it’ll be ready when fertilization occurs) Ovulation (Day 14) 4) When endometrium is ready, a sharp rise in Luteinizing hormone, push ovum out of follicles to form corpus luteum. (Luteinizing means luteum formation) 2) Follicles secrete estrogen when stimulated by FSH 3) Estrogen builds up endometrial wall Follicular phase of ovarian cycle (Day 6 – 14) 1) FSH from anterior pituitary stimulates ovarian follicles Thus, before ovulation, the hormones increased are FSH, LH and Estrogen. Progesterone increases after ovulation. HBS12@Ngee Ann Polytechnic Oct2024  When fertilization did not occur, Corpus luteum degenerates Decreased progesterone production It cannot maintain thickened endometrium Endometrium breaks down and shed at day 28 or at the end of the cycle. Menstruation occurs! HBS12@Ngee Ann Polytechnic Oct2024  When fertilization occurs Spermatozoa + Ovum  Zygote (in the fallopian tube) Zygote divides (mitosis) to become embryo The embryo implants in the endometrium (in the uterus) and placenta is formed. Placenta produces human chorionic gonadotropin (HCG) (8-11 days after fertilization) HCG maintains corpus luteum and progesterone level increased Thickened endometrium layer is maintained. When fertilization happens  no menstruation. HCG produced from placenta is detected by pregnancy test. HBS12@Ngee Ann Polytechnic Oct2024  Regulation of Female Reproductive Hormones (Hypothalo-Pituitary-Gonad Axis) GnRH from hypothalamus stimulates anterior pituitary Anterior Pituitary produces FSH & LH FSH & LH stimulate ovary to produce estrogen & progesterone HBS12@Ngee Ann Polytechnic Oct2024 Clinical conditions Persistent vaginal infection  Ascend up to uterus and fallopian tube  scar tissue formation  It prevents sperm from meeting the ova  infertility. Three Structural defects for Infertility in Blocked fallopian tubes female due to infections, endometriosis leading to 1) Scar tissue scar tissue formation  prevent sperm formation in uterus & from meeting the ova  prevent fallopian fertilization, leading to infertility tube 2) Blocked fallopian tube 3) Fibroid in Fibroids: non malignant tumors, commonly the uterus found at the uterus  prevent implantation HBS12@Ngee Ann Polytechnic Oct2024 Sagittal section of Male Pelvis Rectu m Urinary bladder Seminal vesicle Prostat e Ductus deferens Epididymis Testis HBS12@Ngee Ann Polytechnic Oct2024  Testes Produce sperm and sex hormones Ducts where sperm matured and Epididymis some sperm are stored The male reproductive structures Vas deferens Conduct and store sperm Contribute nutrients and fl uid to Seminal vesicles semen Contributes fl uid to Prostate gland semen Urethra Conducts sperm Contribute mucus- Bulbourethral containing fl uid to glands semen Organ of sexual Penis intercourse HBS12@Ngee Ann Polytechnic Oct2024  Anatomy of a sperm HBS12@Ngee Ann Polytechnic Oct2024  Clinical notes Parameters of semen analysis & their normal range HBS12@Ngee Ann Polytechnic Oct2024  Spermatogenesis Spermatogenesis occurs in the seminiferous tubules Cell division, mitosis & meiosis and maturation (spermiogenesis) HBS12@Ngee Ann Polytechnic Oct2024 Route of sperm through male reproductive Seminiferous structures tubules Epididymis Ductus deferens Ejaculatory duct Penis HBS12@Ngee Ann Polytechnic Oct2024  The Accessory Glands Produce fluid component of semen The The Bulbo- Seminal Prostate urethral Gland Gland Glands HBS12@Ngee Ann Polytechnic Oct2024  Clinical notes Undescended testes: A testicle that hasn't moved into the scrotum Retrieved from: http://napaurology.com/wp-content/uploads/normal-vs-enlarged-prostate.jpg before birth May have fertility issue and increase risk of testicular carcinoma. Benign prostatic hyperplasia (BPH) occurs in elderly men Enlarged prostatic gland  may lead to urinary obstruction HBS12@Ngee Ann Polytechnic Oct2024  Official Open All the Best … 73 HBS12@Ngee Ann Polytechnic Oct2024