Science Flashcards
What are the three body planes?
*Sagital/lateral- left and right
*transverse/ axial- top and bottom
*coronal/frontal- front and back
What is the difference between medial and lateral?
medial means nearer to the midline of the body. Lateral refers to structures further away from the body midline, at the sides.
what does proximal mean and what term of anatomic direction is the opposite?
proximal refers to structures closer to the center of the body. Distal refers to structures further away from the center of the body.
what do the terms anterior, posterior, and inferior mean, respectively?
*anterior- structures in front
*posterior- structures behind
*superior- above, or closer to the head
*inferior- below, or closer to the feet
What are the abdominal quadrants?
divide into 4 quadrants with the umbilicus at the center.
*right upper
*right lower
*left upper
*left lower
What structures comprise the respiratory system and what is its primary function?
it includes the nose, mouth, nasal cavity, sinuses, pharynx, larynx, trachea, bronchial tree, and lungs. These organs facilitate the delivery of oxygen to the cells of the body for use in cellular respiration and help remove waste in the form of carbon dioxide.
Secondary functions of the respiratory system include pH regulation of the blood, thermoregulation, odor detection, and production of speech.
What is the generalized structure of the lungs?
The lungs are spongy, porous organs that occupy most of the thoracic cavity? A serous membrane called the pleura lines the thoracic cavity (parietal pleura) as well as the surface of the lungs (visceral pleura).
The three-lobed right lung is separated by from the two-lobed left lung by the mediastinum.
The trachea forks into primary bronchi which enter the left and right lung (along with blood and lymphatic vessels) at the region called the hilum.
What are the divisions of the passages to the lungs?
The trachea splits into two primary bronchi (one for each lung), which splits repeatedly into secondary branch, tertiary bronchi, and bronchioles to form the bronchial tree. The terminal bronchioles further divide into respiratory bronchioles, which are characterized by the presence of some alveoli. The respiratory bronchioles lead into alveolar ducts, which terminate in alveolar sacs.
What is the general mechanism for breathing?
When the diaphragm and external intercostals contract, the volume of the thoracic cavity increases, and the rib cage and sternum elevate and expand outward.
The increase in volume results in a decrease in intrapleural pressure, and the air enters the lungs in a process called inspiration.
As the volume of the thoracic cavity decreases, intrapleural pressure increases, and air leaves the lungs in the more passive process of expiration.
How is the circulatory system involved in thermoregulation?
Thermoreceptors detect changes in temperature and send impulses to the hypothalamus, which then sends signals to the effectors (smooth muscles that surround cutaneous arterioles). if the body temperature is too warm, the smooth muscle relaxes, and the arterioles dilate to allow more blood to flow through the capillary beds near the surface of the skin, so more heat is lost to the surroundings. if the temperature is too cool, the opposite occurs.
What are the three layers of the heart?
The outer layer is the epicardium, which protects the heart and secretes lubricating serous fluid. The middle layer is the muscular myocardium, which contracts to pump blood. The innermost layer is the endocardium, which lines the chambers and valves.
What are the different valves of the heart and their respective functions?
The tricuspid valve (right AV valve) prevents back flow into he atrium when the ventricle contracts. The pulmonary semilunar valve prevents the return of blood into the right ventricle. The bicuspid valve (also called the left AV valve or mitral valve) prevents blood from entering the left atrium when the ventricle contracts. The aortic semilunar valve stops the backflow of the blood into the left ventricle as it leaves through the aorta.
What is blood pressure, and what do the two numbers indicate?
The force per unit area that is exerted by the blood on the walls of the vessels. The first number refers to the systolic pressure, or the maximum pressure when the ventricles contract, forcing blood into the aorta and pulmonary trunk. Diastole is the period in which the ventricles relax and blood pressure is at its lowest point; diastolic pressure is the bottom number.
What are the primary differences between the systemic and pulmonary circulation?
Because the systemic circuit is much longer than the pulmonary circuit, blood pressure is higher. In the systemic circuit, blood in the arteries carries more oxygen than blood in the veins (the opposite is true for pulmonary circulation). When oxygen levels are low, vessels in the systemic circuit dilate to promote blood flow to tissues that need it, but in pulmonary circulation low blood oxygen triggers vasoconstriction, which redirects blood to better ventilated parts of the lung.
What are the components of the ECG, and what cardiac events do they correspond to?
The P wave represents depolarization of the atria on an ECG. This is followed by the QRS interval, which represents depolarization of the ventricle> Next follows the ST segments and T wave, corresponding to depolarization of the ventricle. A small U wave may follow the T wave and represents further depolarization of the ventricle.
What is the structure and function of elastic arteries?
They are the largest arteries (includes the aorta and major branches). They stretch when blood is forced out of the heart, and recoil under low pressure.
The tunica media (the middle layer) has more elastin than any other vessels.
What are the three types of capillaries?
- continuous capillaries- have a nonporous continuous endothelium; most common type, most impermeable.
- fenestrated capillaries- have pores that increase their permeability; found in the kidneys and small intestines.
- sinusoidal capillaries- have a discontinuous endothelium that permits the passage of large particles and even blood cells; most permeable capillaries.
What is peripheral resistance and what are the main factors that affect it?
The resistance of the vessels to the flow of blood as a result of friction. As resistance increases, blood flow rate decreases. The main factors that affect peripheral resistance are diameter and length of the vessels, and volume and viscosity of the blood.
Resistance is most affected by changes in the diameter of the vessel. The relationship is inverse; as radius decreases, the resistance increases proportionally to the fourth power of the radius.
What is the approximate composition of blood?
- 55% plasma (a solution of water, plasma proteins (albumin, antibodies, clotting proteins), carbohydrates, amino acids, lipids, vitamins, salts, gases, hormones, and waste products. About 92% of plasma water)
- 45% formed elements: red (42-46%) and white blood cells and platelets (together less than 1%)
How is heart rate controlled?
The sympathetic division of the autonomic nervous system increases the heart rate by releasing norepinephrine (NE), which acts on the SA node. The parasympathetic division has the opposite effect. The vagus nerves that innervate the heart release acetylcholine (Ach), which slows HR. Central and peripheral chemoreceptors also help to regulate heart rate by monitoring levels of pH, carbon dioxide and oxygen.
How does the body control blood pressure?
By baroreceptors in the aortic arch and carotid arteries (both of which detect high blood pressure) and also the vena cavae, pulmonary veins, and atrial walls (all of which detect low blood pressure). BP is also regulated by hormones. When BP drops, the kidneys secrete renin, which initiates a series of reactions that ultimately cause the release of aldosterone from the adrenal glands. Aldosterone promotes the reabsorption of water, increasing the plasma volume.
How does ingested food move through the digestive tract?
*swallowing, which consists of three phases: the voluntary buccal phase and the involuntary pharyngeal and esophageal phases.
*peristalsis: involuntary radial contraction and relaxation of the muscularis externa of the digestive tract.
* segmentation of the small intestine and haustral contractions in the large intestine: non-adjacent portions of the intestines involuntarily contract and relax to move the chyme.
What are the four types of cells in the gastric glands of the stomach mucosa?
*Endocrine cells (G cells) release hormones such as gastrin into the blood.
* Parietal cells secrete intrinsic factor (required for the absorption of vitamin B12 in the small intestine), and hydrochloric acid (HCl), which lowers pH of gastric juice.
* Chief cells secrete pepsinogen and gastric lipase.
*Mucous cells secrete bicarbonate-containing mucus to protect the stomach from the acidity and digestive enzymes.
What are the four main regions of stomach?
- Cardiac region: area where food is emptied into the stomach.
*Fundus: most superior region of the stomach. - Body: the largest, most central region, curves toward the right to form a “J” shape, with a lesser curvature and greater curvature.
*Pylorus: funnel-shaped region below the body. The pyloric sphincter is the valve that regulates the release of small amounts of chyme into the small intestine.
How do muscle contractions occur?
When an action potential (electrical signal) reaches a muscle fiber, calcium ions are released. According to the sliding filament model of muscle contraction, these calcium ions binds to the myosin and actin, which assists in the binding of the myosin heads of the thick filaments to the actin molecules of the thin filaments. ATP released from glucose provides the energy necessary for the contraction.
What is bile and what is its function?
Bile is a yellow-green solution of bile salts, pigments (mainly bilirubin from the breakdown of hemoglobin), cholesterol, and electrolytes. Only the bile salts play a role in digestion, and they do so mechanically (not enzymatically) by emulsifying fats into smaller globules called micelles that can be acted on by lipase in the small intestine. Bile enhances the absorption of the fat-soluble vitamins. Liver cells synthesize bile salts from cholesterol.
What are the primary roles of the liver?
Production of bile, metabolic functions like blood sugar regulation, and detoxification.
What are the three primary layers skin is composed of, respectively, from superficial to deep?
*Epidermis: consists entirely of epithelial cells, doe not contain any blood vessels. Most epidermal cells are keratinized.
* Dermis: consists mostly of connective tissue, contains blood vessels, sensory receptors, hair follicles, sebaceous glands, and sweat glands. The dermis also contains elastin and collagen fibers.
* Hypodermis: subcutaneous layer consists of fat and connective tissue, which binds the skin to the underlying muscles, and helps insulate.
What are the functions of the pancreas?
As an endocrine gland, it releases insulin, glucagon, and somatostatin into the blood. As an exocrine gland, acing cells of the pancreas release enzyme-rich juices in response to CCK. Secretin is secreted as well, stimulating the duct cells to release a bicarbonate-rich solution that raises the pH. Pancreatic amylase digests starch, and pancreatic lipase digests fats. Proteases are released in their inactive form, but are activated int he small intestine. Nucleases digest nucleic acids.
Where does most chemical digestion take place?
The small intestine.
Brush border enzymes of the microvilli (as well as pancreatic enzymes) break down carbohydrates, fats, proteins, and nucleic acids into smaller components which are then absorbed.
What are the three regions of the small intestine?
- Duodenum: shortest and widest; receives chyme from the stomach and neutralizing digestive juices form the pancreas.
Most of the chemical digestion of food occurs here; only really absorbs iron.
*Jejunum: main site of absorption; dense microvilli.
*Ileum: longest, narrowest absorbs vitamin B12, bile salts, and any nutrients that were not absorbed by jejunum.
What are the primary functions of the large intestine?
By the time chyme reaches the large intestine, most of the water (approximately 80%) has already been absorbed by the small intestine. As the chyme is pushed through the colon 90% of the remaining liquid is absorbed, leaving a mass of indigestible food, water, and bacteria.
What are the primary regions and structures of the large intestine?
The largest intestine begins at the ileocecal valve, which leads to a pouch called the cecum, which receives chyme from the small intestine. it is also the site of a blind-ended tube called the appendix. The middle portion is the colon, further subdivided into the ascending colon, transverse colon, descending colon, and sigmoid colon (becomes the rectum, which opens to the anus).
what is the enteric nervous system and how does it function?
It is the network of neurons buried the lining of the gastrointestinal tract that controls the function of the digestive system.
the ENS can operate independently of the brain and spinal cord, and communicates with the CNS through the parasympathetic and sympathetic nervous systems. The parasympathetic nervous system stimulates digestive activities, while the sympathetic nervous system inhibits them.
What is the difference between the efferent and afferent division of the PNS, and what type of signal do each carry?
The efferent division delivers motor messages from the CNS to muscles or glands (called effectors), while afferent division of the PNS brings sensory information to the CNS.
In what ways does the nervous system work particularly closest with the endocrine system?
Nerve impulses send information about the condition of the body to the hypothalamus, which regulates the release of hormones from the pituitary, which controls other glands.
All body systems ultimately require direction from the nervous system to function properly and maintain homeostasis. Heart rate, digestion, body temperature, movement, and higher functions such as cognitive ability, memory, emotion, and fine motor skills are under control of the nervous system.
What is sensory adaptation and what are the two primary categories of receptors in terms of their rate of sensory adaptation?
The change in sensitivity that occurs when receptors are exposed to a prolonged stimulus. Phasic receptors (most tactile and chemoreceptors) quickly adapt to a constant stimulus, meaning that action potentials decrease over time and eventually stop. Tonic receptors (proprioceptors, nociceptors, photoreceptors) adapt slowly, constantly alerting the CNS of the stimulus with action potentials.
What are the division of the PNS and what does each of them do?
The autonomic system (ANS) and somatic nervous system (SNS). The SNS controls voluntary movements, such as the contraction of skeletal muscles. The ANS controls involuntary movements, such as the contraction of smooth and cardiac muscles, and glandular secretions. The ANS has two subdivisions that tend to work antagonistically. The sympathetic division activates the “fight or flight” response. The parasympathetic division activates the “rest and digest” functions.
Physiologically, how does the sympathetic nervous system exert its function?
Preganaglionic neurons of the sympathetic nervous system release acetylcholine (ACh), which is the stimulus for the release of norepinephrine from postganglionic neurons. Norepinephrine acts on target tissues, prompting a rapid and unified response.
What are mechanoreceptors?
Sensory receptors that respond to changes in pressure or tension.
Cutaneous touch receptors such as Meissner’s corpuscles, Merkel’s disks, Pacinian corpuscles, and Ruffini endings are all mechanoreceptors, as are the muscle spindles that detect stretching of skeletal muscle and the receptors of the inner eat that detect vibrations.
What do chemoreceptors and nociceptors do?
Chemoreceptors such as olfactory and taste receptors detect the presence of chemicals. Nociceptors detect pain.
What are the four main lobes of the brain and their primary respective functions?
*frontal lobe: short term and working memory and information processing as well as decision-making, planning, and judgement.
*Parietal lobe: toward top of head, sensory input as well as spatial positioning of the body.
*Occipital lobe: back of the head just above the brain stem; visual input, processing, and output; specifically nerves from the eyes enter directly into this lobe.
*Temporal lobes: left and right sides of the brain; all auditory input, processing, and output.
What are parts of the brain stem and their respective functions?
The brain stem (midbrain, pons, medulla oblongata) is an important part of respiratory, digestive, and circulatory functions.
*Midbrain: vision and hearing functions
*Pons: communicates between cerebrum and medulla
*Medulla: connects the spinal cord to the brain; it has an important role with the ANS in the circulatory and respiratory system.
What are the functions of the meninges and basic characteristics of each?
They line the cavity, surround the brain and the spinal cord, and contain cerebrospinal fluid it the subarachnoid space.
The vascularized Pia mater is adhered to surface of the brain and the spinal cord. The arachnoid mater contains connective tissue but not nerves of blood vessels. The enervated, vascularized dura mater lies next to the bones and folds inward, separating the brain onto different compartments.
What are the names and functions of each of the 12 pairs of cranial nerves?
- Olfactory: smell
- Optic: sight
- Oculomotor: moves eye, adjusts the pupil and lens
- Trochlear: moves eye
- Trigeminal: chewing, face sensation
- Abducens: moves eye
- Facial: facial expression and anterior two-thirds of the tongue
- Vestibulocochlear: sound
- Glossopharyngeal: swallowing, saliva, and taste
- Vagus: PNS control
- Accessory: swallowing and movement of the head and neck
- Hypoglossal: speech and swallowing, tongue muscles
What are the two layers of the spinal cord?
It is made of an exterior layer of white matter that surrounds an interior core grey matter.
The white matter consists of glial cells and myelinated bundles of axons that form tracts to and from the brain. There are no cell bodies or dendrites in white matter. Grey matter consists mostly of interneurons, but some motor neurons and glial cells. (The axons are mostly unmyelinated, giving the tissue its grey appearance.)
How do afferent and efferent fibers enter/exit the spinal cord?
Afferent fibers enter into the posterior/dorsal aspect of the spinal cord (a region called the posterior grey horn) through the anterior root, while efferent fibers exit on the anterior/ventral aspect (the anterior grey horn) through the posterior root.
The cell bodies of afferent neurons reside in dorsal root ganglia, just outside the spinal cord.
What is a reflex arc?
A neural pathway that triggers a reflex action.
It begins with the receptor- the site or organ that receives the stimulus. A sensory neuron carries the impulse along the afferent pathway to the integration center within the CNS. Interneurons process the information and pass the impulse to a motor neuron. The impulse travels along the efferent pathway to the effector- the responding muscle or gland.
What are positive and negative feedback loops, respectively?
Positive feedback loops are less common and sometimes harmful because they enhance the stimuli rather than inhibit them. Negative feedback loops inhibit the stimulus or the deviation from homeostasis to bring the body back to the set point.
What are the structural components of a neuron?
*Cell body (soma): contains a nucleus with a prominent nucleolus, organelles, no centrioles.
*Axon: smooth, cable-like nerve fiber that is specialized to conduct electrical impulses away from the soma. Most neurons have one long axon, but the axon’s length can vary, and some neurons have no axon at all.
* Dendrites: relatively short, branched extensions of the cell body that receive neurotransmitters from the other neurons.
What is myelin and what does it do?
A lipid-based coating that insulates the axon of many neurons much like the coating on electrical wire. It also increase the rate an impulse can travel.
What types of cells myelinate neurons in the PNS and CNS, respectively?
Neurons of the peripheral nervous system are myelinated by Schwann cells. Oligodendrocytes sheath the neurons of the central nervous system.
What is neuroglia?
Glial cells support and protect neurons within the central and peripheral nervous system.
Despite their inability to conduct impulses, there are many more glial cells than neurons within nervous tissue.
What are the types and the respective functions of PNS and CNS glial cells, respectively?
*CNS: astrocytes (Anchor neurons, exchange between capillaries and neurons, uptake excess ions and neurotransmitters), microglia (immune defense, digest teas debris), oligodendrocytes (produce myelin sheaths), ependyma (circulate CSF) (CSF- cerebral spinal fluid).
*PNS: satellite cells (surround and cushion PNS neurons), Schwann cells (produce myelin sheaths)
What happens when an action potential reaches the axon terminal?
Voltage-gated calcium channels open in response to the depolarization of the membrane. Calcium ions enter, triggering the release of neurotransmitters by exocytosis. The neurotransmitters diffuse across the synaptic cleft, binding to receptors in the target cell and eliciting either an excitatory or an inhibitory response.
The neurotransmitters are then recycled back to the presynaptic cell, degraded by enzymes, or diffused away from the synaptic cleft to prevent overstimulation.
In what ways does the muscular system respond when thermoreceptors detect a drop in temperature?
*Smooth muscles in the walls of the cutaneous arterioles contract involuntary to reduce the blood flow near the surface of the skin to minimize heat loss
*Arrector pili muscles contract, causing hairs to stand on end to trap warm air
*The shivering reflex is triggered by the posterior hypothalamus; contraction of skeletal muscles requires the hydrolysis of ATP, and this exothermic reaction releases energy in the form of heat.
What body movements occur in the sagittal plane and what does each involve?
*Flexion: Decreases the angle between two body parts (bending the elbow)
*Extension: Increases the angle between two body parts (straightening the elbow)
*Dorsiflexion: Ankle flexion (moving the toes toward the shin)
*Plantar flexion: Ankle extension (moving the toes towards the ground/pointing the toes)
What body movements occur in the frontal plane and what does each involve?
*Adduction: movement toward the midline/to the body (bringing the arm to the body)
*Abduction: Moving away from the midline
*Elevation: Scapula superior movement (shoulder shrug)
*Depression:Scapula inferior movement
*Inversion: Lifting the medial border of the foot. Bring the sole of the foot to face inward.
*Eversion: lifting the lateral border of the foot. Bring the sole of the foot to face outward
What body movements occur in the transverse plane and what do each involve?
*Pronation: Rotating the hand and wrist medially from the bone. If supine, the hand would have the palm to the floor
*Supination: Rotating the hand and wrist laterally from the bone
*Horizontal adduction: The angle between two joints decreases in the horizontal plane
*Horizontal abduction: The angle between two joints increases in the horizontal plane
*Rotation: Pivoting or twisting on the axis (turning the head left and right)
Structurally, how do skeletal, smooth, and cardiac muscles differ?
*Skeletal: Voluntary and striated; the muscle fibers have alternating regions of light and dark bands. A single skeletal myocyte is cylinder-shaped and has many nuclei
*Smooth: involuntary; cells are spindle-shaped, non-striated, and uninucleated
*Cardiac: involuntary; cells are branched, striated, and usually uninucleate (but may have two nuclei). They are connected to each other by intercalated discs with gap junctions that allow the cells to communicate
What is a sarcomere?
The small, repeating unit in the contractile apparatus of a skeletal muscle.
Tens of thousands of these sarcomeres lie end to end to form a myofibril. One sarcomere is separated from another by a boundary called the Z line, where a network of proteins serves as a point of anchorage for actin (thin filaments)
How are motor pathways of the ANS arranged?
They consist of two neurons: a preganglionic neuron and a postganglionic neuron.
The cell body of a preganglionic neuron resides in the CNS and synapses with the cell body of one or more postganglionic neurons within an autonomic ganglion. Postganglionic nerve fibers extend to the effectors. Preganglionic neurons of both the sympathetic and parasympathetic systems release acetylcholine (ACh). Postganglionic neurons of the parasympathetic division release ACh; those of the sympathetic division release norepinephrine.
What are the major structures of the internal male genitalia and their functions?
The internal male genitalia include the epididymis, vas deferens, and accessory glands including the seminal vesicles, prostate gland, and Cowper’s glands (the bulbourethral glands). Sperm pass from the epididymis through the vas deferens (sperm duct), ejaculatory duct, and urethra, and exit through the penis. The seminal vesicles secrete fluid into the ejaculatory duct. Secretions of the prostate gland nourish the sperm and increase their motility. Cowper’s glands secrete a lubricating fluid.
What are the major structures of the internal female genitalia and their functions?
The internal female genitalia include the ovaries, the Fallopian tubes, the uterus, and the vagina. The ovaries produce oocytes and secrete sex hormones.
When an oocyte is released during ovulation, it is captured by the Fallopian tube.
The uterus is a muscular, pear-shaped organ that nourishes and protects the developing embryo. The neck of the uterus that opens to the vagina is called the cervix. The vagina is a muscular canal that receives the penis during intercourse. During childbirth, the baby passes through the vagina, also called the birth canal.
What are the major structures of the external male genitalia and their functions?
The external male genitalia include the penis and scrotum. The penis is the erectile organ responsible for delivering sperm to the female. The scrotum is the sac that protects the sperm-producing testes and keeps them at the proper temperature.
What are the major structures of the external female genitalia and their functions?
The external female genitalia include the structure of the vulva, including the mons pubis, the labia major and labia minor, Bartholin’s glands, and the clitoris. The mons pubis is a mound of fatty tissue that lies over the pubic bone. The skin folded of the labia help to protect the more delicate tissues beneath. Bartholin’s glands produced a fluid that lubricates the vagina. The clitoris consists of the erectile tissue full of nerve endings that contribute to sexual arousal.
What occurs in each of the three phases of ovarian cycle?
*Follicular phase: FSH stimulates the maturation of the follicle, which then secretes estrogen. Estrogen helps to regenerate the uterine lining that was shed during menstruation.
*Ovulation: induced by a surge in LH.
*Luteal phase: Begins with the formation of the corpus lute from the remnants of the follicle, which secretes progesterone and estrogen, which inhibits FSH and LH.
What occurs in each of the three phases of the uterine cycle?
*Proliferative phase: uterine lining is regenerated.
*Secretory phase: endometrium becomes increasingly vascular, and nutrients are secreted to prepare for implantation.
*Menstruation: unless there is implantation, the endometrium is shed.
What are the layers of the epidermis?
*Stratum basale: deepest; single layer of cuboidal or columnar cells that adhere to the basement membrane.
*Stratum spinous: 8-10 layers of spiny cells connected by desmosomes.
*Stratum granulosum: 2-5 layers of slightly flattened cells containing granules of keratohyalin.
*Stratum lucidum: 2-5 layers of dead, flattened keratinocytes, and is only present in the palms and soles of the feet.
*Stratum corneum: most superficial; 15-30 layers of dead, keratin-containing squamous cells that prevent water loss.
What are the primary functions of the integumentary system?
Protection (physical barrier to pathogens), sensory reception, thermoregulation, osmoregulation, insulation, vitamin D absorption.
What are two types of seat glands in the body?
Apocrine and eccrine.
Apocrine sweet glands lie pepper in the dermis because eccrine sweat glands secrete sweat directly onto the skin, while the ducts apocrine glands empty into hair follicles. Apocrine glands are found only in certain regions of the body, only activate at the onset of puberty, and have an unclear function.
Eccrine glands are found nearly everywhere, and the secretion and evaporation of sweat helps to cool the body.
What are the major glands of the endocrine system?
The hypothalamus, pineal gland, pituitary gland, thyroid, parathyroid glands, thymus, adrenal glands, gonads, and pancreas.
What is the difference between an endocrine gland and an exocrine gland?
An endocrine gland produces hormones and secretes them directly into the blood without the use of a duct. The circulatory system then delivered the hormones to target organs where they bond to specific receptors.
By contrast, exocrine glands release non-hormone products (sweat, oil, tears, and bile) through ducts to their target locations-usually a cavity or epithelial surface inside or outside the body. Unlike hormones, exocrine products do not bind to receptors.
What is meant by turbulent and laminar blood flow, respectively?
Turbulence is an unsteady, swirling flow of blood that can occur during periods go high velocity, when the blood encounters an obstruction, or when the vessels take. a sharp turn or narrow suddenly.
Laminar flow is steady, streamlined flow of blood that occurs throughout most of the circulatory system.
Turbulent flow usually produces sounds, while laminar flow is silent.
Physiologically, how does the parasympathetic nervous system exert its function?
Both pre- and postganglionic neurons of the parasympathetic nervous system release acetylcholine. The parasympathetic nervous system stimulates events that are slower-paced, and less essential for immediate survival.
The heart rate and respiration rate decrease, blood flow is directed to digestive organs, peristalsis is promoted, pupils constrict, and glycogen is synthesized.
What are the main types of hormones?
Steroids (derived from cholesterol) and non-steroids.
Steroids: (released by the adrenal cortex, testes, ovaries, and placenta) include the sex hormones (estrogens, androgens, progestrone) and the corticosteroids (glucocorticoids and mineralocorticoids). Since these hormones are lipid-soluble, they can diffuse through the cell membrane.
Non-steroids: usually elicit faster response. They cannot diffuse into the cell, and instead bind to receptors on the cell membrane, activating second-messenger systems. Classified into amines, peptides, and proteins.
What hormones are produced in the pituitary gland and what do they do?
*Thyroid stimulating hormone: Targets the thyroid; stimulates the secretion of thyroid hormones.
*Adrenocorticotropic hormone: Targets the adrenal cortex; stimulates the release of glucocorticoids and mineralocorticoids.
*Growth hormone: Targets muscle and bone; stimulates growth.
*Follicle stimulating hormone: Targets the gonads: Stimulates the maturation of sperm cells and ovarian follicles.
*Luteinizing hormone: Targets the gonads; stimulates the production of sex hormones; surge stimulates ovulation in females.
*Prolactin: Targets the mammary glands; stimulates production of milk.
What hormones are produced in the thyroid gland and what they do?
*Triiodothyronine (T3): Targets most cells; stimulates cellular metabolism.
*Thyroxine (T4): Targets most cells; stimulates cellular metabolism.
*Calcitonin: Targets bone and kidneys; lowers blood calcium.
What hormones are produced in the pancreas and what do they do?
*Insulin: Targets the liver, muscle, and adipose tissue; decreases blood glucose.
*Glucagon: Targets the liver; increases blood glucose.
*Growth hormone IH (GHIH; somatostatin): inhibits the secretion of insulin and glucagon.
What hormones are produced in the adrenal cortex and what do they do?
*Mineralocorticoids (aldosterone): Targets the kidneys; increase the retention of NA+ and excretion of K+.
*Glucocorticoids: Target most tissues; released in response to long-term stressors, increase blood glucose (but not as quickly as glucagon).
*Androgens: Target most tissues; stimulates development of secondary sex characteristics.
What hormones are produced in the GI tract and what do they do?
*Gastrin: Targets the stomach; stimulates the release of HCL.
*Secretin: Targets the pancreas and liver; stimulates the realize of digestive enzymes and bile.
*Cholecystokinin (CCK): Targets the pancreas and liver; stimulates the release of digestive enzymes and bile.
What hormones are produced in the ovaries and what do they do?
*Estrogen: Targets the uterus, ovaries, mammary glands, brain, and other tissues; stimulates uterine lining growth, regulates menstrual cycle, facilitates the development of secondary sex characteristics.
*Progesterone: Targets mainly the uterus and mammary glands; stimulates uterine lining growth, regulates menstrual cycle, required for maintenance of pregnancy.
*Inhibin: Targets the anterior pituitary; inhibits the release of FSH.
What path does urine take through the urinary system?
After being filtered by the kidneys, urine is moved by both gravity and peristalsis into the bladder via ureters. The urine then passes through the urethra and out of the body.
How is urine controlled?
Urine is stored in the bladder until contraction of the detrusor muscle (the smooth muscle within the bladder wall) forces urine into the urethra. Contraction of the bladder is controlled by the parasympathetic nervous system. A circular smooth muscle called the internal urethral sphincter relaxes, and (if the timing is appropriate) the voluntary external urethral sphincter relaxes as well, allowing the urine to flow out.
How do the kidneys help maintain the pH balance of the body?
The response from the kidneys is slower, but lasts longer. As blood pH decreases, H+ ions are excreted by the renal tubules via urine (which is now more acidic) and bicarbonate ions are retained. The intercalated cells of the late distal tubule and collecting duct can also generate new bicarbonate ions. The kidneys lower pH by reabsorbing H+ ions and secreting bicarbonate ions.
What is the difference between innate immunity and adaptive immunity?
*Innate immunity refers to the nonspecific first line of defense against pathogens that is static and present at both. It includes mechanical barriers (Skin and mucous membranes), chemical barriers (low pH of gastric juice, interferes that block viral replication, etc.), and processes like fever and inflammation.
- Adaptive immunity develops over time, retaining a memory of encountered antigens, which allows for faster responses in subsequent exposures to that same antigen. The antigen is recognized as foreign, and the appropriate type of cells is selected to combat the pathogen with which it is associated.
What are two main types of lymphocytes that are involved in adaptive immune responses?
T-lymphocytes ( T cells) and B-lymphocytes (B cells).
*T cells mature in the thymus, and are involved in cell-mediated immunity. When they bind to their specific antigen on the surface of an antigen-presenting cell, they proliferate and differentiate into various types of T cells (cytotoxic, memory, regulatory, or helper T cells).
*B cells mature in the bone marrow, and are involved in humoral-mediated immunity. After binding to specific antigens, they differentiate into plasma cells and memory B cells.
What are the main tissues of the immune system and what do they do?
*Bone marrow: Produces hematopoietic stem cells that give rise to all types of blood cells, including lymphocytes. Bone marrow is the site of B cell differentiation.
*Thymus: This is the site of T cell differentiation.
*Spleen: Spenic cords of the red pulp contain an abundance of macrophages and lymphocytes that help to filter aged blood cells, pathogens, and debris from the blood. The white pull is a lymphatic tissue that consists almost entirely of B and T cells, and it provides a place for these lymphocytes to proliferate.
What are antigens and their antibodies?
*An antigen is a substance that elicits a response from the immune system. They can be found on the surfaces of antigenic substances such as viruses, bacteria, fungi, and pollen grains.
*Antibodies are products of B cells that bind to specific antigens. The binding of an antibody to an antigen can disarm the pathogen in a variety of ways. Antibodies can also neutralize the antigen by blocking its ability to attach to cells, or cause it to become insoluble and predicate out of solution. Antibodies also promote inflammation to help slow the spread of infection.
What are the five classifications of bones in the human body?
Long, short, flat, irregular, and sesamoid.
*Long bones function primarily in movement and supporting body weight. (Ex: femur)
*Short bones are roundish or cube-shaped and function in support and stability. (Ex: carpals)
*Flast bones are flattened, thin bones that are suited for protection and muscle attachment (Ex: sternum)
*Irregular bones have complex shapes with their form suited to their function. (Ex: vertebrae)
*Sesamoid bones are found embedded in tendons where there is considerable mechanical stress. (Ex: patella)
What are the three types of bone cells in the human body?
- Osteoblasts take calcium from the blood, and produce the matrix (including collagen fibers) that forms bone. When it is completely encased in matrix, the osteoblast differentiates into mature bone cell called an osteocyte.
*Osteocytes are the most abundant bone cells, and they maintain the matrix by recycling calcium salts.
*Osteoclasts are large multinucleate cells that are formed by the fusion of monocytes (large white blood cells). They reside on bone surfaces and secrete acid and digestive enzymes that break down bone and return calcium to the blood.
What is the difference between ligament and tendons?
*Ligaments connect bones and help to stabilize joints.
*Tendons connect muscles to bones or other structures, such as the eyeballs, and facilitate movement.
They are both composed of dense regular connective tissue, which consists of bundles of collagen fibers as well as elastic fibers. This gives them strength and resistance to stretching. The collagen fibers of tendons are more densely packed that those of ligaments. They are also arranged in parallel bundles, while the fibers of may ligaments are not. Tendons are tougher, but ligaments are more elastic.
What are cells, and what does every cell contain?
*The basic structural and functional unit of a living organism.
They all contain nucleic acids, cytoplasm, and a cell membrane.
From smallest to largest, what is the hierarchy of levels of organization in an organic.
*Cells are grouped together in tissues.
*Tissues are grouped together in organs.
*Organs are grouped together in systems.
*Organ systems are grouped together and work in tandem to form a complete functioning organism.
What is a nucleus?
A membrane-bound structure that encloses nearly all the genetic material of a eukaryotic cell.
Eukaryotic DNA molecules wrap around associated proteins to form linear chromosomes, and the genes within them are regulated by molecules within the nucleoplasm. For this reason, the nucleus is deemed the “control center” of the cell.
How are prokaryotic and eukaryotic cells different?
Prokaryotic cells do not contain a membrane-bound nucleus, and they do not have membrane-bound organelles. Additionally, while prokaryotes reproduce by simple process called binary fission, eukaryote undergo a more involved method of division called mitosis.
What is the function of ribosomes?
Synthesizing proteins from amino acids.
Ribosomes are numerous, making up about one quarter of the cell. Some cells contain thousands of ribosomes. Some are mobile and some are embedded in the rough endoplasmic reticulum.
What is the function of the Golgi apparatus?
Synthesizing materials such as proteins that are transported out of the cell.
It is located near the nucleus and consists of layers of membranes.
What is the function of the cytoskeleton?
It helps maintain cell shape and structure, move materials within the cell, and move the cell itself. It stabilizes most of the organelles and also provides a “railway” for motor proteins to direct vesicles to their destinations. it also helps anchor the cell to neighboring cells and can forma extensions such as cilia and flagella. In cell division, it separates sister chromatids, and pinches the cell into daughter cells during cytokinesis.
What is the function of endoplasmic reticulum?
It is a tubular network that comprises the transport system of a cell.
It is fused to the nuclear membrane and extends through the cytoplasm to the cell membrane. Two types of endoplasmic reticulum are tough (has ribosomes on the surface) and smooth (does not have ribosomes on the surface).
What are the functions of mitochondria, and what is unique to them in terms of most other organelles?
They perform various functions such as generating ATP, and are also involved in cell growth and death.
Mitochondria contain their own DNA that is separate from that contained in the nucleus.
What are the functions of mitochondria, and what is unique to them in terms of most other organelles?
They perform various functions such as generating ATP, and are also involved in cell growth and death.
Mitochondria contain their own DNA that is separate from that contained in the nucleus.
What is the function of lysosomes?
These organelles break down various substances. They bad from Golgi apparatus, and enclose hydrolytic enzymes that would damage the cell if not separated from the systole. Lysosomes play a vital role in cell homeostasis by dismantling various substrates and nonfunctioning intracellular components, and recycling them in a process called autophagy.
What are the primary differences between cilia and flagella?
Flagella are usually much longer than cilia.
Cilia are almost always found in high numbers, while cells rarely have more than a few flagella.
When cilia move, they do so in back-and-forth strokes, much like oars on a rowboat. Flagella move differently; they are more whip-like with an undulating, beating pattern. Unlike cilia, they are only used for locomotion.
What is the composition of plasma membrane, and how does this structure and composition affect its function?
*A double layer of phospholipids that form a fluid-like barrier that is reinforced by cholesterol and protein molecules.
Since the phospholipids orient themselves with their fatty acid chains pointed inward, the interior of the membrane is hydrophobic, which causes the membrane to remain intact in its aqueous environment, while being somewhat impermeable to substances that are soluble in water.
What is osmosis?
The diffusion of water across a semipermeable membrane. The net movement of water is down its concentration gradient, meaning it will move from an area of higher water concentration to lower, or lower solute concentration to higher.
Osmosis can help to restore balance when solute cannot cross the membrane (or if it can’t cross fast enough to maintain homeostasis).
What is passive transport?
Passive transport is the movement of substances across a cell membrane without the input of energy. Random motion of particles will lead to the net movement of substances down their concentration gradients in a spontaneous process that leads to an increase in entropy.
Simple diffusion, osmosis, and facilitated diffusion are all forms of passive transport.
What is facilitated diffusion and does it require ATP?
Facilitated transport is passive transport (no ATP needed) wherein proteins are used to transport substances down their concentration gradients. Large, polar, and/or charged substances require shielding from the interior of the membrane, and they may use channel or carrier proteins to assist in their transport.
What is active transport and for what sort of processes is it required?
It is an energy-requiring process used to move substances into or out of the cell, usually again their concentration gradients.
It’s required for processes such as the maintenance of a membrane potential, and the uptake of glucose by intestinal cells.
What are endocytosis and exocytosis and do they require ATP?
They are types of active transport that employ vesicles to import and export large particles or bulk quantities of small particles, respectively.
While these processes require ATP, they do not necessarily move solutes against their concentration gradients.
What is mitosis, what preceded it, and what follows it?
The stage of the cell cycle in which the nucleus divides, It alternates with a much longer stage called interphase in which the cell performs its normal functions and prepares for division by copying organelles and duplicating chromosomes. Mitosis is usually followed by cytokinesis, division of the cytoplasm, and results in two genetically identical daughter cells with the same number of chromosomes as the parent cell.
What are the primary events in each of the four phases of mitosis?
*Prophase: Chromatin condenses into chromosomes, nucleolus and nuclear membrane break down, mitotic spindle begins to form
*Metaphase: Spindle aligns the chromosomes along the metaphase plate
*Anaphase: Sister chromatids are split at the centromere and pulled toward opposite poles
*Telophase: Chromosomes uncoil, nuclear membrane forms around each set of chromosomes, nucleolus forms in each new nucleus, mitotic spindle breaks down, cytokinesis begins
What are the phases of the cell cycle?
G1 (first gap), S (synthesis), G2 (second gap), and M (the mitotic phase).
Many cells, however, enter a non-growing G0 state in which the cell performs its job but does not divide. This may happen for a number of reasons, and it is not always reversible. Cells that are deficient in nutrients or growth factors may be blocked from proceeding to the S phase, and only called back to the cycle when favorable conditions are restored.
What happens in the G1 phase of the cycle?
The volume of the cel increases, and the metabolic activities that inhibited during mitosis are accelerated. The cell begins the task of crying its organelles, synthesizing mRNA, tRNA, and rRNA, and producing the enzymes required for DNA replication, all while continuing to perform its given function.
What happens before the cell is allowed to proceed to the S phase?
It is inspected at the G1 checkpoint. It passes if it has grown enough and has sufficient nutrients and growth factors, and the DNA is not damaged, If it fails, it enters the G0 phase.
What happens in the S phase of the cell cycle?
Each molecule of DNA is replicated, doubling the genetic content from 2n to 4n. Note that this does not change the ploidy of the cell; the chromosome number remains at 46. Centrosomes are duplicated. (policy means the number of SETS of chromosomes)
By the end of the S phase, there is an identical copy of each DNA molecule, ensuring that each daughter cell that is created during the M phase will have a complete genome.
What happens before the cell is allowed to divide?
It must pass inspection at the G2 checkpoint. If any errors are detected in the duplicated chromosomes, the cell cycle is arrested until the DNA can be repaired.
Cells that are significantly and irreparably damaged will enter a state of senescence or be eliminated through programmed cell death.
How is meiosis different than mitosis?
Mitosis is a single division that results in two identical cells, each with the same number of chromosomes as the parent cell. In meiosis, a germ cell undergoes two rounds of cell division. During meiosis I, homologous pairs of chromosomes exchange portions of their DNA before they are separated and distributed to daughter cells, and the chromosome number is halved. The steps of meiosis II are similar to those of mitosis and result in four haploid cells.
What does potency refer to in regard to cells?
The ability of a cell to differentiate.
Only totipotent cells (the zygote and cells that arise after the first few divisions) have complete potency, but pluripotent (A cell that is able to develop into many different types of cells or tissues in the body) stem cells still have great differentiation potential. They can develop into any cell type, with the exception of placental cells. As the zygote and subsequent blastomeres undergo cleavage, totipotent cells give rise to two lineages: trophoblast cells, and the embryonic stem cells that give rise to the primary germ layers.
What is apoptosis and how is it involved with embryonic development?
Programmed cell death.
This regulated process is used to eliminate abnormal, mispositioned, or misplaced cells. It also helps to sculpt certain structures like the hands and feet.
What is the structure of DNA?
DNA has a double helix shape.
It consists of nucleotides (a five-carbon sugar, a phosphate group, and a nitrogenous base). The bases are attached to each other with hydrogen bonds, which are easily dismantled so replication can occur. Each base is attached to a phosphate and to a sugar. There are four types of nitrogenous bases: Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
What are transcription and translation?
Transcription is the process in which RNA polymerase copies DNA into RNA. DNA unwinds itself and serves as a template while RNA is being assembled. The DNA molecules are copied to RNA. Translation is the process whereby ribosomes use transcribed RNA to put together the needed protein.
Transfer RNA is a molecule found in the cytoplasm that helps in the translation process.
What are Mendel’s laws?
The law of segregation (the first law) and the law of independent assortment (the second law).
The law of segregation states that there are two alleles and that half of the total number of alleles are contributed by each parent organism.
The law of independent assortment states that traits are passed on randomly and are not influenced by other traits. The exception to this is linked traits.
What is a gene and what is the relationship between genes, genotypes, and phenotypes?
A gene is a portion of DNA that identifies how traits are expressed and passed on in an organism.
Collectively, all genes form the genotype of an individual. The genotype includes genes that may not be expressed, such as recessive genes. The phenotype is a physical, visual manifestation of genes. It is determined by the basic genetic information and how genes have been affected by their environment.
What is monohybrid cross, and what is the ratio of dominant to recessive gene manifestation?
A cross involving only one trait. The ratio of dominant gene manifestation to recessive gene manifestation is 3:1 (DD, Dd, dD, dd) when both parents have a pair of dominant and recessive genes.
If one parent has a pair of dominant genes (DD) and the other has a pair of recessive (dd) genes, the recessive trait cannot be expressed in the next generation because the resulting crosses all have the Dd genotype.
What is the difference between anabolic and catabolic reactions?
Anabolic reactions build larger and more complex molecules from smaller ones. Catabolic reactions break larger molecules from smaller ones. Catabolic reactions release energy, while anabolic ones require energy.
The four basic organic macromolecules produced by anabolic reactions are:
*Carbohydrates
*nucleic acids
*proteins
*lipids
The four basic building blocks involved in catabolic reactions are:
*monosaccharides
*amino acids
*fatty acids
*nucleotides
What are carbohydrates?
Carbohydrates are the primary source of energy and are responsible for proving energy as they can be easily converted to glucose. Oxidation of carbohydrates provides cells with most their energy.
Carbohydrates are involved in the metabolic energy cycles of photosynthesis and respiration.
Structurally, carbohydrates usually take the form of some variation of CH2O as they are made of carbon, hydrogen, and oxygen. Carbohydrates (polysaccharides) are broken down into sugars or glucose.
What are lipids?
Lipids are molecules that are soluble in nonpolar solvents, but are hydrophobic, meaning they do not bond well with water or mix well with water solutions. Lipids have numerous C-H bonds. In this way, they are similar to hydrocarbons (substances consisting only of carbon and hydrogen). The major roles of lipids include energy storage and structural functions. Examples of lipids include fats, phospholipids, steroids, and waxes.
What are proteins?
Proteins are macromolecules formed from amino acids. They are polypeptides, which consist of many (10-100) peptides linked together.
Enzymes are proteins with strong catalytic power. They greatly accelerate the speed at which specific reactions approach equilibrium. Although enzymes do not start chemical reactions that would not eventually occur by themselves, they so make these reactions happen faster and more often. This acceleration can be substantial, sometimes making reactions happen a million times faster.
What are nucleic acids?
Nucleic acids are macromolecules that are composed of nucleotides. Nucleic acids store information and energy and are also important catalysts. It is the RNA that catalyzes the transfer of DNA genetic information into protein coded information.
What is the cycle of infection?
*Reservoir host: The pathogen exists in an environment that allows it to live and multiply.
*Portal of exit: The pathogen must have a means to escape the confines of its environment.
*Mode of transmission: The pathogen must be able travels and to survive outside of a host for a sufficient amount of time to find a new host.
*Portal of entry: Once a new host is found, the pathogen needs a means to enter the new host.
*Susceptible host: The pathogen must be able to take root and successfully infect the host.
What are the phases of bacterial growth in a bacterial infection?
*Lag phase: Microorganisms become accustomed to their new environment. There is little to no growth during this phase.
*Log phase: Bacteria logarithmic (exponential) growth begins. The rate of growth is the most rapid and constant.
*Stationary phase: The rate of growth stagnates due to lack of nutrients and build-up of toxins. Meanwhile, bacteria are dying at a faster rate, so the population stabilizes.
*Death phase: Cell numbers decrease as growth stops and existing bacteria continue to die off.
What are viruses and how are they classified?
Viruses are sub-microscopic and considered non-living because they lack cell structures. Viruses consist of nucleic acids encapsulated in a protein coating called a capsid. The purpose of viruses is to reproduce, but they require a host cell with a protein receptor to which a virus must bind to penetrate the cell membrane.
What is the basic structure of an atom?
Atoms consist of a nucleus and orbiting electrons. The nucleus consists or protons and neutrons.
The nucleus has considerably more mass than the surrounding electrons.
What are ions?
Ions are atoms that are positively or negatively charged.
Protons are positively charged, while electrons are negatively charged. Atoms that have an equal number of protons and electrons are electrically neutral. If the number of protons is not equal to the number of electrons in an atoms, the atom has a positive or negative charge and is an ion.
What are atomic number and atomic mass?
Atomic number refers to the number of protons in the nucleus of an atom. Each element has a unique atomic number. The atomic mass (also known as the mass number) is the total number of protons and neutrons in the nucleus of an atom.
The atomic mass (A) is equal to the number of protons (Z) plus the number of (N). This can be represented by the equation A= Z + N. The mass of electrons in an atom is basically insignificant because it is so small.
What are isotopes?
Isotopes are atoms of the element that vary in their number of neutrons.
Isotopes of the same element have the same number of protons and thus the same atomic number. They are denoted by the element symbol, preceded in superscript and subscript by the mass number and atomic number, respectively. For instance, the notations for protium, deuterium, and tritium are respectively: 1H1, 2H1, and 3H1.
What are the three primary types of chemical bonds and what are their characteristics?
*Ionic bond: When an atom gains or loses electrons, it becomes negatively or positively charged and turns into an ion. An ionic bond is a bond between two oppositely charged ions.
*Covalent bond: Atoms share electrons. Electrons shared equally have a non-polar bond; electrons shared unequally have a polar bond.
*Hydrogen bond: A molecule with a hydrogen atom is strongly attracted to a nearby atom with a pair of unbounded electrons. Hydrogen bonds can also form between two different parts of the same molecule, as in the structure of DNA and other large molecules.
Alkanes, alkenes, and alkynes are organic compounds called hydrocarbons.
*Alkanes have only single bonds between their carbon atoms. Alkanes are saturated hydrocarbons because they contain as many hydrogen atoms as possible due to their single bonds.
*Alkenes have at lease one double bond between two of their carbon atoms. Alkenes are unsaturated (having one or more double bond)
*Alkynes have at least one triple bond between two of their carbon atoms. Like alkenes, alkynes are unsaturated (having one or more double bond)
How is the periodic table arranged?
The table is organized in horizontal rows called Periods, and vertical columns called Groups or Families. Groups of elements share predictable characteristics, the most important of which os that their outer energy levels have the same configurations of electrons.
Elements in periods also share some common properties, but classifications rely more heavily on groups.
What are the three primary states of matter and their characteristics?
*Gas- Assumes volume and shape of its container. Low density. High compressibility. Very free molecular motion.
*Liquid- Volume remains constant, but it assumes shape of its container. High density. Virtually incompressible. Molecules move past each other freely.
*Solid- Definite volume and shape. High density. Virtually incompressible. Molecules vibrate around fixed positions.
What are intensive properties?
Intensive properties do not depend on the amount of matter or quantity of sample. This means that intensive properties will not change if the sample size is increased or decreased.
Intensive properties include color, hardness, melting point, boiling point, density, ductility, malleability, specific heat, temperature, concentration, and magnetization.
What are extensive properties?
Extensive properties depend on the amount of matter or quantity of the sample. Therefore, extensive properties change if the sample size is increased or decreased. If the sample size is increased, the property increases. If the sample size is decreased, the property decreases.
Extensive properties include volume, mass, weight, energy, entropy, number of moles, and electrical charge.
What are the five basic types of chemical reactions?
*Combination reactions: Two or more reactants combine to make one product.
(A + B –> AB)
*Decomposition reactions: A reactant is broken into two or more products.
(AB–> A + B)
*Single displacement: One reaction is displaced by another to form the final product.
(A + BC –> B + AC)
*Double displacement: Ions or bonds are exchanged by two compounds to form two different compounds. (AC +BD –>AD + BC)
*Combustion: A sequence of chemical reactions involving fuel and an oxidant that produces heat and sometimes light.
What do the terms dilute and concentrated refer to in the cortex of solutions?
In a solution, the solute is dissolved in the solvent.
The terms dilute and concentrated refer to how much solute is present.
The more solute that is dissolved, the more concentrated is the solution.
The less solute that is dissolved, the less concentrated (and more dilute) is the solution.
What are acids and bases?
The potential of hydrogen (pH) is a measurement of the concentration of hydrogen ions in a substance in terms of the number of moles of H+ per liter of solution.
All substances fall between 0 and 14 on the pH scale. A lower pH indicates a higher H+ concentration, while a higher pH indicates a lower H+ concentration.
Pure water has a neutral pH of 7. Anything with a pH lower than pure water (<7) is considered acidic. Anything with a pH higher than pure water (>7) is a base.
Which statement below accurately describes the function of its element?
A. Collagen is a spongy fatty compound that creates a padding between bones and other structures.
B. Hemoglobin is the amount of red blood cells that are present in blood, which can reflect disease states, hydration, and blood loss.
C. Lymph is tissue that forms into nodes through which blood is filtered and cleaned.
D. An antigen stimulates the production of antibodies.
D. An antigen is any substance perceived by the immune system as dangerous. When the body senses an antigen, it produces an antibody.
What occurs during the anaphase of mitosis?
A. Chromosomes, originally in pairs, separate from their daughters and move to the opposite ends (or poles) of the cell.
B. The mitotic spindle fibers begin to form.
C. The chromosomes align in the middle of the cell.
D. Two nuclei form, surrounded each by a nuclear membrane.
A. There are four phases of mitosis: Prophase, metaphase, anaphase, and telophase. During prophase, the mitotic spindle fibers begin to form. Next, during metaphase, the chromosomes line up in the middle of the cell. Next, in anaphase, the chromosomes, originally on pairs, separate and move to the opposite ends of the cells. Then, during telophase, two nuclei form around the separated chromosomes, each surrounded by a. nuclear membrane.
Which of the following best describes the structures found underneath each rib in descending order?
A. Vein, nerve, artery.
B. Artery, vein, nerve.
C. Vein, artery, nerve.
D. Nerve, vein, artery.
C. The neuromuscular structure found under each rib in descending order is the vein, artery, and nerve.
Which of the following is true regarding the primary function of the spleen?
A. It produces bile to emulsify fats.
B. It filters microorganisms and other forge in substances from the blood.
C. It helps control blood glucose levels and regulates blood pressure.
D. It regulates blood clotting factors.
B. The spleen’s job is to filter the blood by removing dead or dying red blood cells as well as microorganisms. In humans it is found in the left upper quadrant of the abdomen lateral to the liver.
