FATFEM20

URINARY BLADDER The urinary bladder is a hollow muscular organ, which acts as a temporary reservoir of urine brought to it by the ureters. The stored urine is passed out through the urethra, when the bladder is distended enough to feel the desire to micturate. Diagram of the urinary system showing the positions of the urinary bladder.    LOCATION   The urinary bladder is situated in the anterior part of the lesser pelvis immediately behind the pubic symphysis and in front of rectum in male, and uterus in the female.  The location of the urinary bladder varies with the amount of urine it contains and with age.  (i). When the bladder is empty it lies entirely within the lesser pelvis but when it becomes distended with urine, it expands upward and forward into the abdominal cavity.  (ii). In children, the bladder is an abdominopelvic organ even when it is empty because the pelvic cavity is small and the neck of bladder lies at the level of the uppe...

    INTRODUCTION Nephron is defined as the structural and functional unit of kidney. Each kidney consists of 1 to 1.3 millions of nephrons. The number of nephrons starts decreasing after about 45 to 50 years of age at the rate of 0.8% to 1% every year. Each nephron is formed by two parts: 1. A blind end called renal corpuscle or Malpighian corpuscle 2. A tubular portion called renal tubule. Diagram of the nephron     RENAL CORPUSCLE Renal corpuscle or Malpighian corpuscle is a spheroidal and slightly flattened structure with a diameter of about 200 μ. Function of the renal corpuscle is the filtration of blood which forms the first phase of urine formation. Renal corpuscle is situated in the cortex of the kidney either near the periphery or near the medulla. CLASSIFICATION OF NEPHRONS  Based on the situation of renal corpuscle, the nephrons are classified into two types: 1. Cortical nephrons or superficial nephrons: Nephrons having the corpuscles in o...

MICTURITION  INTRODUCTION   Micturition is a process by which urine is voided from the urinary bladder.  It is a reflex process.  However, in grown up children and adults, it can be controlled voluntarily to some extent.   The functional anatomy and nerve supply of urinary bladder and urethra are essential for the process of micturition.  URETHRAL SPHINCTERS There are two urethral sphincters in urinary tract: 1. Internal urethral sphincter 2. External urethral sphinct INTERNAL URETHRA SPHINCTER . This sphincter is situated between neck of the bladder and upper end of urethra. It is made up of smooth muscle fibers and formed by thickening of detrusor muscle. It is innervated by autonomic nerve fibers. This sphincter closes the urethra when bladder is emptied. EXTERNAL SPHINCTER  External sphincter is located in the urogenital diaphragm. This sphincter is made up of circular skeletal muscle fibers, w...

MALE REPRODUCTIVE SYSTEM Reproductive system is as important as well as the human body that is concern with procreation, continuation of life or survival of human species. It is non functional at the early stage of life, although the anatomical structures are already in place but become active at puberty under hormonal influences. Function of the male reproductive system 1. Production of gametes. 2. Transfer of spermatozoa to the female during coitus 3. Production of sex hormone  STRUCTURES Male reproductive system can be divided into: • Primary sex organ: the primary sex organ in the male is the testis which produces the gamete and secrete male sex hormone(androgens) • Secondary sex organ: they are responsible for storage and transportation of spermatozoa. They includes: i. Ducts: epididymis, ductus deferens, ejaculatory ducts and urethra. ii. Accessory glands: seminal vesicles, prostrate and bulbourethra glands. iii. Corpulatory organs: penis Structure-testis, Epididymis and ...

ORAL CAVITY (MOUTH) Is the first part of the digestive tract and only part involved in ingestion of food. It is bounded by: Anteriorly – by the lips Posteriorly - it is continuous with the oropharynx Laterally – by the muscles of the cheeks Superiorly – by the bony hard palate and muscular soft palate Inferiorly – by the muscular tongue and the soft tissue of the floor of the mouth. The walls of the mouth are lined with thick stratified squamous epithelium which can withstand considerable friction. The epithelium on the gum, hard palate, and dorsum of the tongue is slightly keratinized for extra protection against abrasion during eating. The part of the mouth between the gums and cheeks is the vestibule and the remainder of the cavity is the oral cavity (area between the gums and the teeth.   LIPS (LABIA) Lips are mobile, muscular folds surrounding the mouth. They are covered externally by skin and internally by mucous membrane. It extends from the inferior margin ...

TEETH Teeth are hard conical structures set in the alveoli of the upper and lower jaws that are used in mastication and in assisting in articulation. They are the hardest and most characteristically stable tissue in the body. Each individual has 2 sets of teeth (dentitions).  A tooth is identified and described on the basis of whether it is deciduous (primary) or permanent (secondary) teeth. 1. Decidious or temporary teeth:- are usually immature and are present in children. They are usually 20 in numbers (i.e 2 incisors, 1 canine and 2 molar in each half of the jaw). Before eruption, the developing teeth reside in the alveolar arches as tooth buds.  Deciduous teeth begin to erupt after 6 months of birth (starting from lower central incisors) and are all present after 24months. 2. Permanent teeth replace the deciduous teeth starting from the 6th year after birth to 25th year when the whole teeth are expected to have been completed (32 teeth).   CLASSIFICATION T...

THE PHARYNX (THROAT) Is the part of the digestive system posterior to the nasal and oral cavities, extending inferiorly past the larynx. Is a muscular organ and contains a tube (a passage way) that is about 13cm long. It extends from the base of the skull to the inferior border of the cricoids cartilage anteriorly and the inferior border of C6 vertebra posteriorly. It has both digestive and respiratory functions and is divided into the nasopharynx, oropharynx and laryngopharynx.  The nasopharynx is the nasal part of the pharynx; it lies superior to the soft palate and is the posterior extension of the nasal cavities. It is important in respiration. The oropharynx is the oral part of the pharynx, and is bounded superiorly by the soft palate and inferiorly by the base of the tongue, laterally by the palatoglossal and palatopharyngeal arches. It extends from the inferior level of nasopharynx above to the superior border of the epiglottis.  Laryngopharynx extends from the superior...

DIGESTIVE SYSTEM The digestive system consists of the digestive tract (alimentary canal) and some accessory digestive organs. Its function is to prepare food for absorption. DIGESTIVE PROCESSES The activity of the digestive system can be grouped into the following: 1. INGESTION :- this is the process by which food is taken into the digestive tract via the mouth. 2. PROPULSION :- this the process by which food moves  along the alimentary tract and it includes swallowing and peristalsis process. 3. DIGESTION :- this involves 2 processes: mechanical and chemical digestion Mechanical digestion:- this involves mechanical breakdown of food by chewing, mixing of food with saliva by the tongue, churning food in the stomach and segmentation in the small intestine. Chemical digestion:- this involves series of catabolic steps in which complex food molecules are broken down to their chemical building blocks by enzymes secreted into the lumen of the alimentary canal. Chemical digestion begin...

The neuromuscular junction (NMJ) is a synaptic connection between the terminal end of a motor nerve and a muscle (skeletal/ smooth/ cardiac). It is the site for the transmission of action potential from nerve to the muscle. It is also a site for many diseases and a site of action for many pharmacological drugs. It is a junction, connection between a neuron and a muscle fibre. The structure of neuromuscular Junction can be divided into 3 categories ➡️ Presynaptic part( terminal end of an Axon). It consists of vesicles which contains Acetylcholine.  ➡️ Synaptic cleft (space between the neuron and the muscle fibre. ➡️ Postsynaptic part( site of action or the muscles fibre. It contains receptors for neurotransmitters eg. Acetylcholine) PHYSIOLOGY   The nerve impulses reaches the terminal end of a axon, the following will take place. ➡️ The will be opening of the ca+(voltage ⚡) gated channel. ➡️ This will cause the release of the vesicles. ➡️ Vesicles will rupture and r...

When you touch a hot object or when a pin pricks your finger, what is your immediate reaction? Of course, you remove your hand away from the source of pain, either the hot object or the pin. In situations like these, your reactions are always immediate, involuntary and sudden. They happen without much of a thinking process. In scientific terms, this action is called the reflex action. DEFINITION   A reflex is a rapid,  predictable response to a stimulus. TYPES  There are two types ➡️ AUTONOMIC : Autonomic  reflexes  regulate the activity of smooth muscles,  the heart,  and glands.  Secretion of saliva (salivary reflex) and changes in the size of the eye pupils (pupillary reflex) etc.  Autonomic reflexes regulate such body functions as digestion,  elimination,  blood pressure,  and sweating. ➡️ SOMATIC :Somatic  reflexes  include all reflexes that stimulate the skeletal muscles.  When you quickly pull your hand a...

 The ventricular system is a set of communicating cavities within the brain. These structures are responsible for the production, transport and removal of cerebrospinal fluid, which bathes the central nervous system. FUNCTIONS OF CEREBROSPINAL FLUID  Cerebrospinal fluid is an ultrafiltrate of plasma that surrounds the brain and spinal cord. It serves three main functions : ➡️ Protection : acts as a cushion for the brain, limiting neural damage in cranial injuries. ➡️Buoyancy : by being immersed in CSF, the net weight of the brain is reduced to approximately 25 grams. This prevents excessive pressure on the base of the brain. ➡️Chemical stability : the CSF creates an environment to allow for proper functioning of the brain, e.g. maintaining low extracellular K+ for synaptic transmission. VENTRICLES OF THE BRAIN  The ventricles are structures that produce cerebrospinal fluid, and transport it around the cranial cavity. They are lined by ependymal cells, which fo...

MENINGES The term meninges comes from the Greek for "membrane" and refers to the three membranes that surround the brain and spinal cord. The membrane layers (discussed in detail below) from the outside in are the: dura mater, arachnoid mater, and pia mater. Their positioning around the brain can be seen in the image to the right. DURA MATER  The dura mater is the outermost layer of the meninges, lying directly underneath the bones of the skull and vertebral column. It is thick, tough and inextensible. Within the cranial cavity, the dura contains two connective tissue sheets: ➡️ Periosteal layer  lines the inner surface of the bones of the cranium. ➡️Meningeal layer    deep to the periosteal layer inside the cranial cavity. It is the only layer present in the vertebral column. Between these two layers, the dural venous sinuses are located. They are responsible for the venous vasculature of the cranium, draining into the internal jugular veins. ARACHNOID ...

SPINAL CORD The spinal cord is an elongated cylinder of neuron cell bodies, bundles of axons and other cells, protected by connective tissue and bone. It connects to the brain at the medulla oblongata and runs down the vertebral column, the hollow tunnel enclosed within the vertebrae of the spine. ➡️ Function: The spinal cord is part of the central nervous system and serves as a kind of superhighway. Sensory information and motor commands travel up and down, heading to and from the brain.    CLINICAL CORRELATION : Arteriovenous malformations, meningitis, multiple sclerosis, neural tube defects, polio and post-polio syndrome, spina bifida, spinal muscular atrophy, Syringomyelia.  MENINGES   The meninges are the three layers of connective tissue that surround and protect the brain and spinal cord. These are the dura mater, arachnoid mater, and pia mater.  ➡️  BRAIN 🧠  The BRAIN is  the upper, expanded part of the central nervous system...