BIO 106 - Systems of the body

Endoskeleton and Exoskeleton What is an exoskeleton? What is an endoskeleton?

*Exoskeleton* -An *exoskeleton* = is *an external skeleton consisting of a hard encasement on the surface of an organism* -For example, the shells of crabs and insects are exoskeletons -This *skeleton type provides defense against predators*, *supports* the body, and *allows for movement* through the contraction of attached muscles. As with vertebrates, muscles must cross a joint inside the exoskeleton. Shortening of the muscle changes the relationship of the two segments of the exoskeleton. Arthropods such as crabs and lobsters have exoskeletons that consist of 30-50 percent chitin, a polysaccharide derivative of glucose that is a strong but flexible material. *Chitin is secreted by the epidermal cells*. The exoskeleton is further strengthened by the addition of calcium carbonate in organisms such as the lobster. Because the exoskeleton is acellular, arthropods must periodically shed their exoskeletons because the exoskeleton does not grow as the organism grows. *Endoskeleton* -An *endoskeleton* is a skeleton that *consists of hard, mineralized structures in the soft tissue of organisms*. An example of a primitive endoskeletal structure is the spicules of sponges. The bones of vertebrates are composed of tissues, whereas sponges have no true tissues (Figure 38.4). Endoskeletons *provide support for the body,* *protect internal organs*, and *allow for movement* through contraction of muscles attached to the skeleton. The skeletons of humans and horses are examples of endoskeletons.The human skeleton is an endoskeleton that consists of 206 bones in the adult. It has five main functions: providing support to the body, storing minerals and lipids, producing blood cells, protecting internal organs, and allowing for movement. The skeletal system in vertebrates is divided into the axial skeleton (which consists of the skull, vertebral column, and rib cage), and the appendicular skeleton (which consists of the shoulders, limb bones, the pectoral girdle, and the pelvic girdle).

Encoding and Transmission of Sensory Information What are the four aspects of sensory info encoded by sensory systems? What types of stimuli?

*Four aspects of sensory info encoded by sensory systems*: *1.* the *type of stimulus* *2.* the *location of stimulus in receptive field* *3.* the *duration of stimulus* *4.* the *relative intensity of the stimulus* -Thus, *action potentials transmitted over a sensory receptor's axons encode 1 type of stimulus*, and this *segregation of senses is preserved in other sensory circuits* -For example, auditory receptors transmit signals over their own dedicated system, and electrical activity in the axons of the auditory receptors will be interpreted by the brain as an auditory stimulus—a sound. The intensity of a stimulus is often encoded in the rate of action potentials produced by the sensory receptor. Thus, an intense stimulus will produce a more rapid train of action potentials, and reducing the stimulus will likewise slow the rate of production of action potentials. A second way in which intensity is encoded is by the number of receptors activated. An intense stimulus might initiate action potentials in a large number of adjacent receptors, while a less intense stimulus might stimulate fewer receptors. Integration of sensory information begins as soon as the information is received in the CNS, and the brain will further process incoming signals.

Sexual activity can transmit disease

*Sexually transmitted diseases (STDs)* are also called sexually transmitted infections (STIs) and are contagious diseases spread by sexual contact. Not all STDs can be treated equally. Those caused by bacteria, protozoans, and fungi can be cured with medications. Viral STDs cannot. For bacterial STDs, treatment must be given early, before any permanent damage is done. -*Chlamydia* and *Gonorrhea* = *genital discharge*, *painful urination* is the most common bacterial STD, often produces no symptoms, and *can lead to PID* pelvic inflammatory disease and *infertility* -*Genital Herpes* = *genitalia herpes*, *painful urination*, skin inflammation, linked to *cervical cancer* Viral diseases such as genital herpes, *papillomavirus (HPV)*, and HIV can only be controlled -*Genital Warts* = *painless growth on genitalia*, some strains linked to cancer AIDS, caused by HIV, poses one of the greatest health challenges in the world today. In the United States, there are 56,000 new infections each year, one-third of which result from heterosexual contact. Latex condoms, relatively cheap and easily distributed, can help prevent the spread of HIV. But how effective are they? *Candidiasis* (yeast infections) = *vaginal irritation, itching, discharge* One study, published in 2007 by the World Health Organization of the United Nations, followed more than 800 couples in which one partner was HIV-positive and the other was not. Of these couples, 587 reported always using condoms, while 276 reported never using condoms. The data showed an 80% reduction in the rate of infection with condom use. Although viral STDs cannot be cured, many other STDs can be effectively treated if addressed early. If left untreated, an STD may lead to long-term problems or even death. Anyone who is sexually active should have regular medical exams, be tested for STDs, and seek immediate help if any suspicious symptoms appear, even if they are mild. STDs are most prevalent among teenagers and young adults. Nearly two-thirds of infections occur among people under 25. The best way to avoid the spread of STDs is, of course, abstinence. Alternatively, latex condoms provide the best protection for "safe sex."

Aerobic respiration supplies most of the energy for exercise What constant supply is required fro aerobic respiration? What step in cellular respiration does this correspond to?

-*Aerobic respiration* requires a constant *supply of glucose and oxygen* and provides most of the ATP used to *power muscle* movement during exercise. -The *anaerobic process of lactic acid fermentation* can *provide ATP faster than aerobic respiration* but is less efficient. The motion of muscle shortening occurs as myosin heads bind to actin and pull the actin inwards. This action requires energy, which is provided by ATP. Myosin binds to actin at a binding site on the globular actin protein. Myosin has another binding site for ATP at which enzymatic activity hydrolyzes ATP to ADP, releasing an inorganic phosphate molecule and energy. ATP binding causes myosin to release actin, allowing actin and myosin to detach from each other. After this happens, the newly bound ATP is converted to ADP and inorganic phosphate, Pi. The enzyme at the binding site on myosin is called ATPase. The energy released during ATP hydrolysis changes the angle of the myosin head into a "cocked" position. The myosin head is then in a position for further movement, possessing potential energy, but ADP and Pi are still attached. If actin binding sites are covered and unavailable, the myosin will remain in the high energy configuration with ATP hydrolyzed, but still attached. If the actin binding sites are uncovered, a cross-bridge will form; that is, the myosin head spans the distance between the actin and myosin molecules. Pi is then released, allowing myosin to expend the stored energy as a conformational change. The myosin head moves toward the M line, pulling the actin along with it. As the actin is pulled, the filaments move. approximately 10 nm toward the M line. This movement is called the power stroke, as it is the step at which force is produced. As the actin is pulled toward the M line, the sarcomere shortens and the muscle contracts. When the myosin head is "cocked," it contains energy and is in a high-energy configuration. This energy is expended as the myosin head moves through the power stroke; at the end of the power stroke, the myosin head is in a low-energy position. After the power stroke, ADP is released; however, the cross-bridge formed is still in place, and actin and myosin are bound together. ATP can then attach to myosin, which allows the cross-bridge cycle to start again and further muscle contraction can occur

Introduction of Reproduction System What is asexual reproduction? What is sexual reproduction?

-*Animal reproduction* is necessary for the *survival of a species* -In the *animal kingdom*, there are *innumerable ways that species reproduce* -*Asexual reproduction* = produces *genetically identical organisms (clones)* -whereas in *sexual reproduction* = the *genetic material of 2 individuals combine to produce offspring* that are genetically *diff from their parents* -During *sexual reproduction* = the *male gamete (sperm) may be placed inside* the female's body *for internal fertilization*, or the sperm and eggs may be released into the environment for *external fertilization* -Seahorses, provide an example of the latter. Following a mating dance, the female lays eggs in the male seahorse's abdominal brood pouch where they are fertilized. The eggs hatch and the offspring develop in the pouch for several weeks -*STDs* can be caused *by pathogens*, including -*bacteria* -*protists* and -*fungi* -*Viral STDs* are uniquely *problematic*, because *viruses can hide within a cell* making them very *difficult to eradicate* -Although *STDs from other types of pathogens* = *successfully treated*, -*Viral STDs* = *cannot be cured and so last a lifetime* -Prevention of infection through safe sex practices is the best option for remaining uninfected

Bone Cells What 3 things do bone cells do? What is osteoporosis? What type of bone is easily fractured in osteoporosis?

-*Bone cells* -*repair* bones and -*reshape* bones throughout life. -*Broken bones* are *realigned* and *immobilized*, and bone cells *build new bone*, *healing the break* *Osteoporosis* is a *bone disease* characterized by *low bone mass* and structural deterioration and *spongy bones are easily fractured in osteoporosis* less likely if a person -has high levels of calcium in the diet, -has sufficient intake of vitamin D, -exercises regularly, and -does not smoke.

Bone Bone/osseous tissue is what kind of tissue that constitutes the endo or exoskeleton? It has specialized cells and what does it consist of? What are the 6 types of bones? What is fibrous connective tissue? What do long bones have what 3 things?

-*Bone/osseous tissue* is a *connective tissue that constitutes the endoskeleton* -It contains *specialized cells* and a *matrix of mineral salts* and *collagen fibers* -The *mineral salts* primarily include hydroxyapatite, a mineral formed from calcium phosphate. Calcification is the process of deposition of mineral salts on the collagen fiber matrix that crystallizes and hardens the tissue. The process of calcification only occurs in the presence of collagen fibers. The bones of the human skeleton are classified by their shape: *long bones, short bones, flat bones, sutural bones, sesamoid bones, and irregular bones* -*Fibrous connective tissue* covering most of the *outer surface of bone* forms *new bone if fracture* -*Cartilage at ends of bones* + *cushions joints* and *reduces friction* of movements + *lubrication* but wears out over time leading to arthritis -*Bone* contains *living cells secreting a surrounding material*, or matrix. The *matrix consists of flexible fibers of protein collagen*, which *keep bones flexible*, and *crystals of a mineral = (HIGHEST RESERVOIR) calcium and phosphate*, which *resists compression* -*Long bones* have a *central cavity w/ fatty yellow bone marrow* and *spongy bone at the ends* of bones containing *red bone marrow*, a specialized tissue that *produces blood cells* -Long bones are longer than they are wide and have a *shaft and two ends*. The diaphysis, or central shaft, contains bone marrow in a marrow cavity. The rounded ends, the epiphyses, are covered with articular cartilage and are filled with red bone marrow, which produces blood cells. Most of the limb bones are long bones—for example, the femur, tibia, ulna, and radius. Exceptions to this include the patella and the bones of the wrist and ankle.

Brain Structures and Functions What is the brainstem and what does it include? What is the medulla oblongata? What is the pons? What is the midbrain What does cerebellum do? What does the thalamus do? What does the hypothalamus do? What does the cerebrum do?

-*Brainstem* = includes the midbrain, medulla oblongata, and the pons. conducts *data to/from other brain centers*; maintains *homeostasis*; coordinates *body movement* -*Medulla oblongata* = controls *breathing, circulation, swallowing, digestion* -*Pons* = controls *breathing* -*Midbrain* = *receives* and *integrates auditory data*; coordinates *visual reflexes*; sends *sensory data to higher brain centers* -*Cerebellum* = coordinates *body movement*; plays role in *learning/remembering motor responses*, controls the *balance* -*Thalamus* = serves as *input center for sensory data* going to the *cerebrum*; *sorts/groups incoming data* for cerebrum -*Hypothalamus* = functions as *homeostatic control center*; controls *pituitary gland*; serves as *biological clock* (sleep/wake cycle) or thermostat, *food/water intake* -*Cerebrum* = performs *sophisticated integration* of info; plays major role in *memory, learning, speech, emotions* + *formulates complex behavioral responses*

Several types of eyes have evolved among animals Evolution has resulted in a great diversity of __________ Animal light detectors are based on what that contain pigment molecules absorbing light What is one of the simplest light detecting organs which senses light direction?

-*Evolution* has *resulted in great diversity of organs* that animals use to perceive light. •All *animal light detectors* are based on *cell-based* = *photoreceptors* that contain *pigment molecules absorbing light* •One of the *simplest light-detecting organs* = the *invertebrate eyecup*, used by planarians, which *senses light direction*

fMRI scans provide insight into brain structure and function

-*Functional magnetic resonance imaging (fMRI)* is a *scanning/imaging tech* used to *study brain* structure and function, is used on *conscious patients* and monitors changes in blood oxygen usage in the brain -Studies using fMRI confirm hypotheses based on older technologies about the roles of specific brain areas in movement and intention. Researchers have applied such techniques to correlate specific brain regions with nearly every aspect of human cognition, consciousness, and emotion. -The *reticular formation* is one example of a *functional brain system regulating alertness* -*Attentiveness/mental alertness* can *change rapidly* -*Arousal* is a *state of awareness of outside world* Its counterpart is sleep, a state when external stimuli are received but not consciously perceived. The reticular formation is a diffuse network of neurons that extends through the core of the brainstem The alertness that is maintained by the reticular formation is inhibited by a region of the hypothalamus that induces and regulates sleep. Sleep is essential for survival and is an active state, at least for the brain. Understanding the function of sleeping and dreaming remains a compelling research problem

Joints and Skeletal Movement What are joints and what do they allow? What are ligaments? What are 3 types of joints and what do they enable? What joint names are ball and socket found in?

-*Joints* allow *lim movement of bones* -*Bands of strong fibrous connective tissue* = called *ligaments* hold together the *bones of movable joints* -The point at which *two or more bones meet* is called a joint, or articulation. Joints are *responsible for movement*, such as the movement of limbs, and stability, such as the *stability found in the bones* of the skull. -Different joints permit various movements. -*Ball-and-socket joints* enable *rotation* in the *arms and legs*. Ball-and-socket joints possess a rounded, ball-like end of one bone fitting into a cuplike socket of another bone. This organization allows the greatest range of motion, as all movement types are possible in all directions. Examples of ball-and- socket joints are the shoulder and hip joints -*Hinge joints* in the *elbows and knees* permit *movement* in a single plane. In hinge joints, the slightly rounded end of one bone fits into the slightly hollow end of the other bone. In this way, one bone moves while the other remains stationary, like the hinge of a door. The elbow is an example of a hinge joint. The knee is sometimes classified as a modified hinge joint -*Pivot joints* enable the *rotation* of the *forearm at the elbow*. Pivot joints consist of the rounded end of one bone fitting into a ring formed by the other bone. This structure allows rotational movement, as the rounded bone moves around its own axis. An example of a pivot joint is the joint of the first and second vertebrae of the neck that allows the head to move back and forth. The joint of the wrist that allows the palm of the hand to be turned up and down is also a pivot joint.

Skeletal Muscle Fiber Structure What do muscle cells consist of? Skeletal muscle cells are (3) Myofibrils have overlapping _____________ filaments and ____________ filaments What are the thick filaments made of? What are thin filaments made of? Which one has an ADP and phosphate head required for the muscle to pull over? What is needed to break this bond? What are sarcomeres?

-*Muscle fibers* are cells that *consist of bundles* of *myofibrils*(Within each muscle fiber are myofibrils—long cylindrical structures that lie parallel to the muscle fiber. Myofibrils run the entire length of the muscle fiber, and because they are only approximately 1.2 μm in diameter, hundreds to thousands can be found inside one muscle fiber. They attach to the sarcolemma at their ends, so that as myofibrils shorten, the entire muscle cell contracts) *Skeletal muscle cells*: -are *cylindrical*, -have *many nuclei*, and -are *oriented parallel* to each other -*Myofibrils contain overlapping* *thick filaments* = composed primarily of the *protein myosin* and *dark band* (Thick filaments occur only in the A band of a myofibril.) *thin filaments* = composed primarily of the *protein actin*, *light band* (attach to a protein in the Z disc called alpha-actinin and occur across the entire length of the I band and partway into the A band.) ATP is needed to break the bond of ADP and actin *Thick and thin filaments are themselves composed of proteins*. Thick filaments are composed of the protein myosin. The tail of a myosin molecule connects with other myosin molecules to form the central region of a thick filament near the M line, whereas the heads align on either side of the thick filament where the thin filaments overlap. The primary component of thin filaments is the actin protein. Two other components of the thin filament are tropomyosin and troponin. Actin has binding sites for myosin attachment -*Sarcomeres* are *repeating groups of overlapping thick/thin filaments* and the *contractile apparatus in a myofibril*—the muscle *fiber's fundamental unit of action* (which are the functional units of skeletal muscle. One sarcomere is the space between two consecutive Z discs and contains one entire A band and two halves of an I band, one on either side of the A band. A myofibril is composed of many sarcomeres running along its length, and as the sarcomeres individually contract, the myofibrils and muscle cells shorten)

A muscle contracts when thin filaments slide along thick filaments What do the myosin heads of the thick filaments do? Myosin heads then attach to binding sites on what molecules and pull the thin filaments where?

-*Myosin heads of the thick filaments* bind ATP and extend to high-energy states -*Myosin heads then* attach to binding sites on the actin molecules and pull the thin filaments toward the center of the sarcomere.

Neurons and Glial Cells Do nervous systems vary or are they all the same? What are some examples? (Sea sponges, jellyfish, echinoderms, flatworms) What is the PNS? (2 things made of) What is the CNS? (2 things made of) What is one interesting difference btwn nervous systems of invertebrates and vertebrates?

-*Nervous systems* throughout the animal kingdom *vary in structure/complexity* -Some organisms, like *sea sponges, lack true nervous system* -Others, like *jellyfish, lack true brain* and instead have a system of *separate but connected nerve cells (neurons)* = *"nerve net"* -*Echinoderms* such as sea stars have *nerve cells bundled into fibers* =called *nerves* -*Flatworms* of the phylum Platyhelminthes have both a *central nervous system (CNS)*, made up of a *small "brain"* and *2 nerve cords* -*Peripheral nervous system (PNS)* containing a *system of nerves* that *extend throughout the body* -The *insect nervous system* is *more complex + fairly decentralized* -It contains a *brain, ventral nerve cord, ganglia* (clusters of connected neurons) -These *ganglia can control movements/behaviors* without input from the brain -*Octopi* may have the most *complicated* of invertebrate nervous systems—they have *neurons* that are organized in *specialized lobes* and eyes that are structurally similar to vertebrate species -Compared to invertebrates, *vertebrate nervous systems* are *more complex, centralized, specialized* -While there is *great diversity in diff vertebrate nervous systems* -They all *share a basic structure*: a *CNS* that *contains a brain/spinal cord* and a *PNS* made up of *peripheral sensory* and *motor nerves* -One interesting difference between the nervous systems of invertebrates and vertebrates is that the *nerve cords of invertebrates* are located *ventrally* whereas the *vertebrate spinal cords* are located *dorsally* -The *nervous system* is *made up of neurons* (specialized cells that can receive/transmit chemical/electrical signal), *glia* (cells that provide support functions for the neurons by playing an information processing role that is complementary to neurons) -A *neuron* can be compared to an *electrical wire*—it *transmits a signal from one place to another* -*Glia* can be compared to the *workers at a electric company* who make sure wires go to the right places, maintain the wires, and take down wires that are broken. Although glia have been compared to workers, recent evidence suggests that also usurp some of the signaling functions of neurons

Hormones synchronize cyclic changes in the ovary and uterus

-*Oogenesis is one part of a female mammal's reproductive cycle*, a recurring sequence of events that *produces gametes*, makes them available for fertilization, and prepares the body for pregnancy. The reproductive cycle is actually two closely linked cycles. The *ovarian cycle* = controls the *growth/release* of an *egg* During the *menstrual cycle* = the *uterus prepares for possible implantation* of an embryo. -Hormonal messages coordinate the two cycles, synchronizing follicle growth in the ovaries and ovulation with the establishment of a uterine lining that can support a growing embryo. The hormone story involves intricate feedback mechanisms.

Perception Perception is simply an individual's interpretation of a _______________

-*Perception* = an *individual's interpretation of a sensation* -Although *perception relies on activation of sensory receptors* + *perception happens not at sensory receptor* but *higher levels* of nervous system in the brain -The *brain distinguishes sensory stimuli* through a sensory pathway: -*action potentials from sensory receptors* (along neurons) that are *dedicated to stimulus* -These *neurons are dedicated to particular stimulus/synapse* w/ particular neurons in the brain or spinal cord -All sensory signals, except those from the olfactory system, are transmitted though the central nervous system and are routed to the thalamus and to the appropriate region of the cortex. Recall that the thalamus is a structure in the forebrain that serves as a clearinghouse and relay station for sensory (as well as motor) signals. When the sensory signal exits the thalamus, it is conducted to the specific area of the cortex dedicated to processing that particular sense. How are neural signals interpreted? Interpretation of sensory signals between individuals of the same species is largely similar, owing to the inherited similarity of their nervous systems; however, there are some individual differences. A good example of this is individual tolerances to a painful stimulus, such as dental pain, which certainly differ.

Hormones of the Ovarian and Menstrual Cycles

-*Releasing Hormone* = secreted *by hypothalamus* and regulates secretion of *LH/PFSH by pituitary* -*Follicle-stimulating hormone* (FSH) = secreted by *pituitary* -*Luteinizing Hormone (LH) = secreted by *pituitary* and stimulates *growth of ovarian follicle*, *prod of secondary oocyte*, development of corpeus luteum (remnant of follicle) -*Estrogen* = secreted by * ovarian follicle*, *LOW levels inhibit pituitary* + *high levels stimulate hypothalamus*; promo growth of endometrium (lining of uterus) -*Estrogen/Progesterone* = *maintain endometrium* secreted by corpeus luteum, menstrual cycle is dependent on this Corpeus Luteum is there in case she gets pregnant, and if she doesn't the lining of endometrium sheds through hormone estrogen CULTURES/SENSITIVITY = STD test

Sensory Processes What do senses provide to the body? What are the five special senses? What is somatosensation? Vestibularsensation? A sensory receptor triggers an action potential and sends info to CNS or PNS?

-*Senses provide info ab the body* and *its environment* -Humans have *five special senses*: olfaction (*smell*), gustation (*taste*), equilibrium (*balance and body position*), *vision*, and *hearing* -Additionally, we *possess general senses* also called *somatosensation*, which *respond to stimuli like temp, pain, pressure, vibration* -*Vestibular sensation* = which is an organism's sense of *spatial orientation and balance* -*Proprioception* (position of bones, joints, and muscles), and the sense of *limb position used to track kinesthesia* (limb movement) are part of somatosensation -Although the *sensory systems are very diff*, all share a *common function*: to *convert a stimulus* (such as light, or sound, or the position of the body) *into an electrical signal* in the nervous system = *sensory transduction* = produces a *change in cell's membrane potential* -There are *2 broad types of cellular systems* that *perform sensory transduction* -In one, a *neuron works w/ a sensory receptor* a cell, or *cell process specialized to engage w/* and *detect a specific stimulus* + *trigger an action potential* and *send info to CNS* -Stimulation of the sensory receptor *activates associated afferent neuron*, which *carries info about stimulus to CNS* -In the *second type of sensory transduction*, a *sensory nerve (receptor) ending responds to a stimulus in the internal/external environment*: this neuron constitutes the sensory receptor -Free nerve endings can be stimulated by several different stimuli, thus showing little receptor specificity. For example, pain receptors in your gums and teeth may be stimulated by temperature changes, chemical stimulation, or pressure.

Sexual Reproduction 2 haploid cells form a _______________ How do sperm move by mean of what? What are hermaphrodites? What do they have both of ? What is internal and external fertilization?

-*Sexual reproduction* = is the creation of *offspring by fertilization*, the *fusion of 2 haploid (n) sex (23 chromosomes) cells*/gametes to *form a diploid (2n) zygote* -The *male gamete* = *sperm* is relatively *small* and *moves by* means of a *flagellum* -The *female gamete* = the *egg* is a much *larger* cell and is *not self-propelled* •*Hermaphroditism* makes it *easier to find a mate for animals solitary/less mobile* •Hermaphrodites may •*exchange gametes w/ other individuals* or *fertilize own eggs* -*Hermaphroditism* occurs in *animals where 1 individual has BOTH male/female reproductive parts* -*Invertebrates* such as earthworms, slugs, tapeworms and snails are often *hermaphroditic* -Hermaphrodites may *self- fertilize/mate w/ their species* fertilizing each other and both producing offspring. Self fertilization is common in animals that have limited mobility or are not motile, such as barnacles and clams. -During *sexual reproduction* the genetic material of two individuals is combined to produce genetically diverse offspring that differ from their parents -The genetic diversity of sexually produced offspring is thought to *give species a better chance of surviving in a changing environment* -Species that reproduce sexually must maintain *2 diff types of individuals*, males and females, which can *limit the ability to colonize new habitats* as both sexes must be present -*External fertilization* = is used by *many aquatic invertebrates*, *fish*, amphibian species. -*Eggs/sperm* are *discharged by each other* -*Fertilization* occurs *in water* -External fertilization usually occurs in aquatic environments where both eggs and sperm are released into the water. After the sperm reaches the egg, fertilization takes place. Most external fertilization happens during the process of spawning where one or several females release their eggs and the male(s) release sperm in the same area, at the same time. The release of the reproductive material may be triggered by water temperature or the length of daylight. -*Internal fertilization* is used by *some fish/amphibian* species and nearly all *terrestrial animals* -*Sperm* is deposited *in/near female reproductive tract* -Fertilization occurs within the female reproductive tract Internal fertilization occurs most often in land-based animals, although some aquatic animals also use this method. There are three ways that offspring are produced following internal fertilization. In oviparity, fertilized eggs are laid outside the female's body and develop there, receiving nourishment from the yolk that is a part of the egg. This occurs in most bony fish, many reptiles, some cartilaginous fish, most amphibians, two mammals, and all birds. Reptiles and insects produce leathery eggs, while birds and turtles produce eggs with high concentrations of calcium carbonate in the shell, making them hard. Chicken eggs are an example of this second type.

types of muscle tissue What 3 types are there? Which ones are involuntary and which one aren't?

-*Skeletal muscle tissue* forms skeletal muscles, which attach to bones or skin and control locomotion and any movement that can be consciously controlled. Because it can be controlled by thought, skeletal muscle is also called *voluntary muscle*. Skeletal muscles are long and cylindrical in appearance; when viewed under a microscope, skeletal muscle tissue has a striped or striated appearance. The striations are caused by the regular arrangement of contractile proteins (actin and myosin). Actin is a globular contractile protein that interacts with myosin for muscle contraction. Skeletal muscle also has multiple nuclei present in a single cell. *Smooth muscle* tissue occurs in the walls of hollow organs such as the *intestines, stomach, and urinary bladder*, and around passages such as the respiratory tract and blood vessels. Smooth muscle has no striations, is not under voluntary control, has only one nucleus per cell, is tapered at both ends, and is called *involuntary muscle* -*Cardiac muscle tissue* is only found *in the heart*, and cardiac contractions pump blood throughout the body and maintain blood pressure. Like skeletal muscle, cardiac muscle is striated, but unlike skeletal muscle, cardiac muscle cannot be consciously controlled and is called *involuntary muscle*. It has one nucleus per cell, is branched, and is distinguished by the presence of intercalated disks.

The skeleton and muscles interact in movement Muscle cells are specialized for what? Muscles and bones interact to produce _______________ Muscles are connected to bones by ___________ and can only ________________

-Muscle cells are *specialized for contraction*. Muscles allow for motions such as walking, and they also facilitate bodily processes such as respiration and digestion. The body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle -*Muscles and bones* interact to *produce movement* -*Muscles* are *connected to bones by tendons* and can *only contract*, requiring an *antagonistic muscle to reverse* the action and *relengthen muscles*

Receiving neuron's membrane may receive signals that are both excitatory and inhibitory How do you inhibit a receiving cell's activity? What are 2 things that excite/make a postsynaptic neuron more likely to fire an action potential? What process do they both cause? What about inhibitory (2)? What do they do to the membrane?

-*Some neurotransmitters* = excite a receiving cell* -Others *inhibit a receiving cell's activity* by *decr its action potentials* The *summation of excitation and inhibition determines if a nerve signal will be transmitted* -*EPSP strong enough to induce an action potential* in the postsynaptic neuron, but often *multiple presynaptic inputs must create EPSPs for the postsynaptic neuron to be sufficiently depolarized for an action potential* -This process is called summation and occurs at the axon hillock. Additionally, one neuron often has inputs from many presynaptic neurons—some excitatory and some inhibitory—so IPSPs can cancel out EPSPs and vice versa. It is the *net change in postsynaptic membrane voltage determines if postsynaptic cell has reached its threshold of excitation* needed to fire an action potential. Together, synaptic summation and the threshold for excitation act as a filter so that random "noise" in the system is not transmitted as important information. -The binding of a specific neurotransmitter causes particular ion channels, in this case ligand-gated channels, on the postsynaptic membrane to open -*Neurotransmitters can either have excitatory/inhibitory effects on postsynaptic membrane* -For example, when *acetylcholine is released at the synapse btwn a nerve and muscle* (called the neuromuscular junction) by a presynaptic neuron, it *causes postsynaptic Na+ channels to open* -*Na+ enters the postsynaptic cell* and causes *depolarization* = *excitatory postsynaptic potential (EPSP)* and *makes the postsynaptic neuron more likely to fire an action potential.* -Release of *neurotransmitter at inhibitory synapses* = causes *inhibitory postsynaptic potentials (IPSPs)* which is a *hyperpolarization of the presynaptic membrane* For example, when the neurotransmitter *GABA* (gamma-aminobutyric acid) is *released from a presynaptic neuron*, it *binds to + opens Cl- channels* *Cl- ions enter hyperpolarizing the membrane*, making the *neuron less likely to fire an action potential* -Once neurotransmission has occurred, the *neurotransmitter must be removed from the synaptic cleft* so the *postsynaptic membrane can "reset" to receive another signal* -This can be accomplished in three ways: the *neurotransmitter can diffuse away from synaptic cleft*, it can be *degraded by enzymes in synaptic cleft*, or it *can be recycled (reuptake)* by the presynaptic neuron. Several drugs act at this step of neurotransmission. For example, some drugs that are given to Alzheimer's patients work by inhibiting acetylcholinesterase, the enzyme that degrades acetylcholine. This *inhibition of enzyme acetylcholinesterase incr neurotransmission at synapses* that release acetylcholine. Once released, the *acetylcholine stays in the cleft* and can continually bind and unbind to postsynaptic receptors.

Synaptic Transmission Synapses are relay points btwn the synaptic terminal and__________ __________ What could the receiving cell be What are the 2 varieties that synapses come in?

-*Synapses* are *relay points btwn synaptic terminal of a sending neuron and a receiving cell* -The *receiving cell can be another neuron/effector cell* such as a muscle cell or endocrine cell. Synapses come in two varieties: -In an *electrical synapse* = electrical *current flows from a neuron via gap junctions* -At *chemical synapse* = the sending *(presynaptic) cell secretes a chemical signal*, a *neurotransmitter, which crosses the synaptic cleft*, and the neurotransmitter *binds to a specific receptor* on the surface of the *receiving (postsynaptic) cell* *1.* There are *Neurotransmitters in the synaptic vessels* *2.* *Vesicle* fuses with *attaches to plasma membrane* *3.* *Neurotransmitter released* into *synaptic cleft* *4.* *Neurotransmitter* binds *attaches to receptor* of the *other effector cell/neuron* *5.* The receptor has an *Ion channel open* + *Na+ ions enter* *6.* Then the *ion channel closes* and the *neurotransmitter is broken down by enzymes* and *taken up*

The human male reproductive system includes the testes and structures that deliver gametes What two things does the testes produce in a sac called what? What does epididymis do? In ejaculation, the sperm leaves epididymis through what? The seminal vesicles secrete what that provides what to the sperm as they propel themselves. The prostate gland secretes what? What glands clean urethra and neutralize remaining urine? Sperm production by the testes is controlled by hormones from?

-*Testes* (singular, testis that produce sperm and male hormones) are each *housed outside abdominal cavity* in a *sac* = called the *scrotum* -The *scrotum keeps sperm-forming cells about 2°C cooler* which allows them to *function* normally + carry and support the testes -A *testis in scrotum* = is called a *testicle* The *epididymis* = *storage/maturation of sperm* as they develop further. -During *ejaculation* = *sperm leave epididymis* through the *vas deferens* -THREE (3) glands contribute to *semen* = the *fluid ejaculated from penis* (deliver urine, copulating organ) *during male orgasm* -The *seminal vesicles* secrete a *thick fluid w/ mucus + sugar fructose* which provides most of the *energy by sperm as they propel* themselves *through female reproductive tract* + contribute to semen prod -The *prostate gland* = secretes a *thin, milky fluid nourishes the sperm* + contribute to semen prod The walnut-shaped prostate gland surrounds the urethra, the connection to the urinary bladder. It has a series of short ducts that directly connect to the urethra. The gland is a mixture of smooth muscle and glandular tissue. The muscle provides much of the force needed for ejaculation to occur. -The *bulbourethral glands* secrete a *clear, alkaline mucus* that *neutralizes acidic urine* remaining *in urethra* + clean urethra at ejaculation The bulbourethral gland, or Cowper's gland, releases its secretion prior to the release of the bulk of the semen. It neutralizes any acid residue in the urethra left over from urine. This usually accounts for a couple of drops of fluid in the total ejaculate and may contain a few sperm. Withdrawal of the penis from the vagina before ejaculation to prevent pregnancy may not work if sperm are present in the bulbourethral gland secretions. T The human penis consists mainly of cylinders of *erectile tissue fill w/ blood to cause an erection* during sexual arousal. During ejaculation, contractions in multiple glands force secretions into the urethra and propel sperm from the epididymis, a sphincter muscle at the base of the bladder contracts, preventing urine from leaking into the urethra from the bladder, and during the expulsion stage, the sphincter at the base of the penis relaxes, admitting semen into the penis. -*Sperm prod by testes* is *controlled by hormones* from the *hypothalamus and pituitary*

Nervous System and Neurons What are the two major organ systems responsible for coordinating functions of the animal body? What's the diff btwn them? What does communication rely on? What are the 2 divisions of the nervous system? Which one is located outside of the other?

-*Two major organ systems* are responsible for coordinating functions of the animal body: -the *endocrine system*, with *slower* and more sustained responses, and -the *nervous system*, with *faster* and less sustained responses -*Communication* within the nervous system *relies on neurons* = *nerve cells* that *transmit info via electrical/chemical signals* -*Nervous systems* usually have *2 divisions*: 1) *The central nervous system (CNS)* consists of the *brain and spinal cord* (vertebrates). 2) *The peripheral nervous system (PNS)* is located *outside the CNS* and consists of *nerves* (bundles of neurons wrapped in connective tissue) and *ganglia*(clusters of neuron cell bodies) -The nervous system of the common laboratory fly, Drosophila melanogaster, contains around 100,000 neurons, the same number as a lobster. This number compares to 75 million in the mouse and 300 million in the octopus. *A human brain* contains around *86 bil neurons* -Despite these very different numbers, the *nervous systems of animals control basic reflexes to more complicated behaviors* like finding food and courting mates. The ability of neurons to communicate with each other as well as with other types of cells underlies all of these behaviors. Most *neurons share the same cellular components* But neurons are also highly specialized—different types of neurons have different sizes and shapes that relate to their functional roles.

Vertebrate skeletons are variations on an ancient theme Vertebrate bodies reveal variations in what? What are homeotic genes? Vertebrate evolution has changes in what?

-*Vertebrate bodies* reveal *variations of basic skeletal arrangement* -*Master control (homeotic) genes* = are *active during early development* and *direct arrangement of the skeleton* -*Vertebrate evolution* has *included changes in master control genes*

Hydrostatic Skeleton What is the hydrostatic skeleton and what is it formed by? What are the organs of coelom supported by? what does MUSCLE and PRESSURE do? (2)

-A *hydrostatic skeleton* = is a *skeleton formed by a fluid-filled compartment in the body* called the *coelom* -The *organs of the coelom* are *supported by aqueous fluid* which also *resists external compression* -This compartment is *under hydrostatic pressure* because of the fluid and *supports the other organs* of the organism - This *movement* in a hydrostatic skeleton is *provided by muscles* that *surround the coelom* -The *MUSCLE in a hydrostatic skeleton contract to change SHAPE of the coelom*; the *PRESSURE of the fluid in the coelom produces MOVEMENT*. For example, earthworms move by waves of muscular contractions of the skeletal muscle of the body wall hydrostatic skeleton, called peristalsis, which alternately shorten and lengthen the body. Lengthening the body extends the anterior end of the organism. Most organisms have a mechanism to fix themselves in the substrate. Shortening the muscles then draws the posterior portion of the body forward. Although a hydrostatic skeleton is well-suited to invertebrate organisms such as earthworms and some aquatic organisms, it is not an efficient skeleton for terrestrial animals.

Parts of a Neuron What are the parts of a neuron? What does each do? Why is cell body necessary? What does a typical axon have at the very end? What is the junction between a synaptic terminal and another neuron/effector cell? What are axons covered in and what do they do? What are Nodes of Ranvier? When is electrical energy used by the neuron and when is chemical energy used?

-Neurons have unique extensions arising from the neuron cell body. 1) *Dendrites* are *highly branched, often short, extensions* that *receive signals* from other neurons and convey this info towardcell body. 2) Cell body , containing the *nucleus/cell organelles* and *long, thin extensions that convey signals* + *REAPIRS DAMAGE IN AXON* 3) *Axons* are typically a much *longer extension* that *transmits signals* to other cells, which may be other *neurons/effector cells* -A typical *axon has hundreds/thousands of branches*, each with a *synaptic terminal* at the very end -The *junction btwn synaptic terminal/neuron/effector cell* is called a = *synapse*, or relay point -At a *synapse* = *electrical/chemical signals* are *transmitted to other neurons/effector cells* -Like other cells, each neuron has a *cell body* = (or soma) that contains a *nucleus, smooth/rough endoplasmic reticulum, Golgi apparatus, mitochondria* and other cellular components -*Neurons* also contain *unique structures* for *receiving/sending electrical signals* to communicate Although some neurons do not have any dendrites, some types of neurons have multiple dendrites. Dendrites can have small protrusions called *dendritic spines incr surface area* for possible synaptic connections -Once a signal is received by the dendrite, it then travels passively to the cell body. The cell body contains a specialized structure, the axon hillock that integrates signals from multiple synapses and serves as a junction between the cell body and an axon -An axon is a tube-like structure that propagates the integrated signal to specialized endings called axon terminals. These terminals in turn synapse on other neurons, muscle, or target organs. Chemicals released at axon terminals allow signals to be communicated to these other cells. Neurons usually have one or two axons, but some neurons, like amacrine cells in the retina, do not contain any axons -*Some axons are covered* with *MYELIN SHEATH*, which acts as an *insulator to minimize excess electrical signal as it travels down the axon* greatly increasing the speed on conduction -This insulation is important as the axon from a human motor neuron can be as long as a meter—from the base of the spine to the toes. The myelin sheath is not actually part of the neuron. *Myelin* is produced by *GLIAL cells* Along the axon there are *periodic gaps in the myelin sheath* = *nodes of Ranvier* and are sites where the *(SODIUM AND POTASSIUM)* *signal is "recharged"* as it travels along the axon It is important to note that a single neuron does not act alone—neuronal communication depends on the connections that neurons make with one another (as well as with other cells, like muscle cells). Dendrites from a single neuron may receive synaptic contact from many other neurons. For example, dendrites from a Purkinje cell in the cerebellum are thought to receive contact from as many as 200,000 other neurons. *Neurons transport information by ELECTRICAL (current action potential)* AND *CHEMICAL (neuron transmitter release)*

Motor neurons stimulate muscle contraction What does a motor neuron carry? An action potential passes along what tubules? What ions are released from the endoplasmic reticulum and bound in what protein resulting in a cross bridge? What does this allow the muscles to do? When motor neurons stop sending action potentials to the muscle fibers _____________ (3) What are 2 potentials exist in a NEURON? Which one is decremental?

-A *motor neuron* carries an *action potential to a muscle cell*, *releases the neurotransmitter acetylcholine* from its synaptic terminal, and *initiates a muscle contraction* An action potential in a muscle cell passes along T tubules and into the center of the muscle fiber. *Calcium ions* are released from the *endoplasmic reticulum and bind to the regulatory protein troponin*, resulting in the movement of tropomyosin away from the myosin-binding sites and allowing contraction to occur. *A motor unit* consists of -a *motor neuron* and -all the *muscle fibers* it controls. -More forceful *muscle contractions result when additional motor units are activated* When motor neurons stop sending action potentials to the muscle fibers = - Ca+2 goes back to ER - Active site (troponin) will block - Muscles stop contractions **If you don't enervate muscle fibers = no contraction A motor unit = motor neuron, muscle fibers - *2 potentials exist in a NEURON* 1. *LOCAL POTENTIAL* = *limited to dendrites* and cell body, *decremental: as it spreads it *gets weaker*, graded = depends on stimulus 2. *ACTION POTENTIAL* =* in axon*, gets *stronger as it spreads, not graded*

Nervous systems receive sensory input, interpret it, and send out commands What are the 3 interconnected functions of a nervous system? What are the 3 neurons that play a role?

-A *nervous system* has *3 interconnected functions*: 1) *Sensory input* is the conduction of *signals fromsensory receptors*, detect change inside/outside of your body, first they integrate where it is coming from (info), produce a response to the brain that does integration, urine in bladder or food in stomach, takes message from body to spinal cord and brain, detects change, pain, touch, temp, stretched organs (bladder/stomach) 2) *Integration* is the analysis and *interpretation of sensory signals in brain/spinal cord* and the *formulation of responses* 3) *Motor output* is the conduction of *signals fromintegration centers through PNS to effector cells*, such as muscle cells or gland cells, which *perform body's responses*, brings back to effector tissue to produce a response *Three functional types of neurons* correspond to a nervous system's three main functions: 1) *Sensory neurons convey* signals from *sensory receptors into the CNS* 2) *Interneurons* are *located in the CNS*, *integrate data*, and *relay appropriate signals to other interneurons/motor neurons* 3) *Motor neurons* convey *signals from CNS to effector cells*

Sliding Filament Model of Contraction What is the sliding filament model of muscle contraction?

-According to the *sliding-filament model of muscle contraction* = a *sarcomere contracts (shortens) when its thin filaments slide along thick filaments* -*Contraction shortens the sarcomere* + *DOESN'T change lengths of thick/thin filaments* -When the *muscle is fully contracted* = the *thin filaments overlap in the middle of the sarcomere* For a muscle cell to contract, the sarcomere must shorten. However, thick and thin filaments—the components of sarcomeres—do not shorten. Instead, they slide by one another, causing the sarcomere to shorten while the filaments remain the same length. The sliding filament theory of muscle contraction was developed to fit the differences observed in the named bands on the sarcomere at different degrees of muscle contraction and relaxation. The mechanism of contraction is the binding of myosin to actin, forming cross-bridges that generate filament movement. When a sarcomere shortens, some regions shorten whereas others stay the same length. A sarcomere is defined as the distance between two consecutive Z discs or Z lines; when a muscle contracts, the distance between the Z discs is reduced. The H zone—the central region of the A zone—contains only thick filaments and is shortened during contraction. The I band contains only thin filaments and also shortens. The A band does not shorten—it remains the same length—but A bands of different sarcomeres move closer together during contraction, eventually disappearing. Thin filaments are pulled by the thick filaments toward the center of the sarcomere until the Z discs approach the thick filaments. The zone of overlap, in which thin filaments and thick filaments occupy the same area, increases as the thin filaments move inward.

How Neurons Communicate All functions are performed by the ____________ system. Neurons use both_________ and _________ signals For the nervous system to function = the neurons need to be able to _______/_______ signals What does each neuron have and what is the charged membrane? What is resting membrane potential and what are the charges and ions? A neuron at rest is how many millivolts? The neg resting membrane potential is maintained by what? Why does the cell become neg-charged? What does the sodium potassium pump help maintain?

-All *functions performed by nervous system*—from a simple motor reflex to more advanced functions like making a memory or a decision—require neurons to communicate w/ one another -While humans use words and body language to communicate, *neurons use electrical/chemical signals* Just like a person in a committee, one neuron usually receives and synthesizes messages from multiple other neurons before "making the decision" to send the message on to other neurons -For *the nervous system to function* = *neurons* must be *able to send/receive signals* -These *signals are possible* bc *each neuron has a charged cellular membrane* (a voltage difference between the inside and the outside), and the charge of this membrane can change in response to neurotransmitter molecules released from other neurons and environmental stimuli -To understand how neurons communicate, one must first understand the basis of the baseline or 'resting' membrane charge -At *rest* = when a *neuron isn't transmitting a signal*, a neuron's *plasma membrane has potential energy*—the membrane potential, in which just *INSIDE the cell is slightly NEGATIVE* and just *OUTSIDE the cell is slightly POSITIVE* -The *resting potential* = is the *voltage across plasma membrane of a resting neuron* - *A neuron at rest* = is *negatively charged*: the inside of a *cell is -70 millivolts* more negative than the outside (−70 mV, note that this number varies by neuron type and by species). This voltage is called the *resting membrane potential* = it is caused by *differences in concentrations of ions inside/outside the cell* -If the membrane were equally permeable to all ions, each type of ion would flow across the membrane and the system would reach equilibrium. Because *ions cannot cross membrane at will* = there are *diff concentrations of ions inside/outside the cell* -The *diff in number of positively charged potassium ions (K+) inside* and *outside* the cell dominates = *resting membrane potential* -When the *membrane is at rest* = *K+ ions accumulate INSIDE the cell* bc of *net movement in concentration gradient* -The *NEG resting membrane potential* = created and maintained by *incr cations Na+ outside the cell*(in the extracellular fluid) relative to inside the cell (in the cytoplasm) -The *neg charge IN the cell bc CELL MEMBRANE IS MORE PERMEABLE TO POTASSIUM ION movement than sodium ion movement* -In neurons, *potassium ions are high concentrations within the cell* while *sodium ions are high concentrations outside of the cell* -The *cell possesses potassium/sodium leakage channels for cations to diffuse down their concentration gradient* -However, the *neurons have MORE potassium leakage channels than sodium leakage channels* -Therefore, *potassium diffuses out of the cell at a much faster rate than sodium leaks in* -Because *more cations are leaving* the cell than are entering, this *causes the interior of the cell to be negatively charged* relative to the outside of the cell. The actions of the sodium potassium pump help to *maintain the resting potential* (compensates for leaky channels that go against the pump movement) once established -Recall that *sodium potassium pumps* brings *2 K+ ions INSIDE cell* while *removing 3 Na+ ions per ATP* consumed -As *more cations are expelled from the cell than taken in*, the *inside remains negative* relative to the extracellular fluid. It should be noted that calcium ions (Cl-) tend to accumulate outside of the cell because they are repelled by negatively-charged proteins within the cytoplasm.

Asexual Reproduction What are the three types of asexual reproduction?

-Although *every animal has a short life span*, species *transcend* this time limit *w/ reproduction*, the creation of new individuals from existing ones. Animals reproduce in a *great variety of ways*, but there are two modes: 1. *asexual* 2. *sexual* -*Asexual reproduction* is the creation of *genetically identical offspring w/ 1 parent* -Asexual reproduction *can proceed via*: -*budding* = the *outgrowth/eventual splitting of a new individual from a parent*, the outgrowth of a part of a cell or body region leading to a *separation from the orig organism into 2 individuals*. Budding occurs commonly in some invertebrate animals such as corals and hydras. In hydras, a bud forms that develops into an adult and breaks away from the main body, whereas in coral budding, the bud does not detach and multiplies as part of a new colony. -*fission* = the *separation of a parent* into *2 or more offspring of equal size*, occurs in *prokaryotic microorganisms* and in some invertebrate, multi-celled organisms. After a period of growth, an organism splits into two separate organisms. Some unicellular eukaryotic organisms undergo binary fission by mitosis. In other organisms, part of the individual separates and forms a second individual. -*fragmentation/regeneration* = the *breaking of parent body into several pieces*, followed by *regeneration* = the *regrowth of lost body parts*, Fragmentation is the breaking of the body into two parts with subsequent regeneration. If the animal is capable of fragmentation, and the part is *big enough, a separate individual will regrow* -*Animals produce offspring* through *asexual/sexual reproduction* -Both methods have advantages and disadvantages -*Asexual reproduction* produces offspring that are genetically identical to the parent because the offspring are all clones of the original parent -A *single individual can produce offspring* asexually and *large numbers of offspring* can be produced quickly -In a *stable environment*, asexual reproduction is effective means of reproduction because all the *offspring will be adapted to that environment* -In an *unstable* or unpredictable environment asexually-reproducing species may be at a disadvantage because all the *offspring are identical + may not have the genetic variation* to survive in new or different conditions. On the other hand, the rapid rates of asexual reproduction may allow for a speedy response to environmental changes if individuals have mutations. An additional advantage of asexual reproduction is that colonization of new habitats may be easier when an individual does not need to find a mate to reproduce

The Central Nervous System The spinal cord is a jelly-like bundle of _______ that run from the spine to brain w/ info What is the membrane of the brain covered w/ involving 3 layers: What are ventricles? What is the outermost layer? What is a network of blood vessels servicing the CNS called? What does the cerebrospinal fluid do for the brain?

-In all vertebrates, the *central nervous system (CNS)* consists of the *brain* = the *master control center* of the nervous system, and the *spinal cord* = a *jellylike bundle of nerve fibers* that runs lengthwise inside the spine, which conveys *info to/from the brain + integrates simple responses to certain stimuli. The vertebrate peripheral nervous system (PNS) comprises the rest of the nervous system. The *central nervous system (CNS)* = *brain* and *spinal cord* and is *covered w/ 3 layers: meninges* (from the Greek word for membrane) -*Ventricles* are *spaces in brain filled w/ cerebrospinal fluid* + *continuous w/ narrow central canal* of the spinal cord. -The *outermost layer* = the *dura mater* which *protects the brain + spinal cord* -The dura mater also contains *vein-like structures carry blood from brain back to the heart* -A vast network of *blood vessels services the CNS*, but a selective mechanism, called the* blood-brain barrier* maintains a *stable chemical environment for the brain*. -The middle layer is the web-like arachnoid mater. The last layer is the pia mater (Latin for "soft mother"), which directly contacts and covers the brain and spinal cord like plastic wrap -The space btwn the arachnoid and pia maters is filled with *cerebrospinal fluid (CSF) produced by a tissue* called choroid plexus in fluid-filled compartments in the CNS called ventricles. The *brain floats in CSF*, which acts as a *cushion and shock absorber* and *makes the brain neutrally buoyant* found in and *around the brain/spinal cord*

Introduction to Sensory System

-In more *advanced animals*, the *senses are constantly at work*, making the animal aware of stimuli—such as light, or sound, or the presence of a chemical substance in the external environment—and *monitoring info about organism's internal environment* -All *bilaterally symmetric animals* have a *sensory system*, and the *development of any species' sensory system* has been *driven by natural selection*; thus, sensory systems differ among species according to the demands of their environments. The shark, unlike most fish predators, is electrosensitive—that is, sensitive to electrical fields produced by other animals in its environment. While it is helpful to this underwater predator, electrosensitivity is a sense not found in most land animals

Changes in brain physiology can produce neurological disorders What are 4 neurological disorders? What is schizophrenia? What is bipolar disorder? What is Alzheimer's disease? What is Parkinson's disease?

-Many *neurological disorders* can be *linked to changes in brain physiology*, including -*schizophrenia* -*major depression* -*Alzheimer's disease* and -*Parkinson's disease* -*Schizophrenia* is a severe mental disturbance characterized by *psychotic eps in which patients have a distorted perception of reality* The physiological causes of schizophrenia are unknown, although the disease has a strong genetic component -*Bipolar disorder* or manic-depressive disorder, is *characterized by extreme mood swings* The manic phase is *marked by high self-esteem*, *incr energy*, and flow of ideas In its milder forms, this *phase is assoc. w/ great creativity* The depressive phase is characterized by lowered ability to feel pleasure, loss of motivation, sleep disturbances, and feelings of worthlessness. -*Alzheimer's disease (AD)* is characterized by *confusion + memory loss* Its incidence increases dramatically with age. Diagnosis of AD is made with a combination of neuropsychological clinical tests and brain imaging -*Parkinson's disease* is a *motor disorder* characterized by difficulty in initiating movements,*slowness of movement*, and rigidity. At present, there is no cure for Parkinson's disease, although various treatments can help control the symptoms.

A variety of small molecules function as neurotransmitters Neurotrasmitters are small, ____________-containing molecules ________________ is released by PNS motor neurons to activate __________ ____________ What are biogenic amines? Many neuropeptides are short chains of ______ _______ and they serve as neurotransmitters Endorphins are ___________ that decr our perception of _________/________ release in response to stimuli What substances affect neurotransmitter action?

-Many *small, nitrogen-containing molecules* are *neurotransmitters* -*Acetylcholine is released* by *PNS motor neurons to activate skeletal muscles*, by other *PNS neurons also affect internal organs/glands(and by *neurons in CNS affect memory, learning, alertness* -*Biogenic amines* are neurotransmitters derived from *amino acids and function in the CNS* -They include *serotonin and dopamine*, which affect *sleep, mood, attention, learning*, and *norepinephrine*, which along with serotonin seems to be linked with some *types of depression* -Many *neuropeptides are relatively short chains of amino acids* also serve as neurotransmitters. -*Endorphins* are *peptides that decr our perception of pain in physical/emotional stress* and may be *released in response to stimuli* including traumatic injury, muscle fatigue, and even eating very spicy foods. -*Nitric oxide* is a *dissolved gas* and *triggers erections* during sexual arousal in men. -Many *psychoactive drugs at synapses* + *prescription disorders* = *affect neurotransmitter* action -*Caffeine counters inhibitory neurotransmitters* -*Nicotine* acts as a *stimulant that binds to* + *activates acetylcholine receptors* Alcohol is a strong depressant. Tranquilizers such as *diazepam (Valium)* and *alprazolam (Xanax) activate receptors for neurotransmitter GABA*, *incr its effect on inhibitory synapses* A drug may *bind/block receptor*, *reduce neurotransmitter's effect* Still other drugs, such as the selective *serotonin reuptake inhibitors (SSRIs) used to treat depression*,act by *inhibiting neurotransmitter "reuptake"* -*Depression* is a prevalent mood disorder in the United States. *Antidepressants are widely prescribed* for this common illness, and antidepressant *SSRIs* bc *depression is caused by deficiency in serotonin*, a regulator of mood.

Human Appendicular Skeleton What is an appendicular skeleton? What do the upper limbs provide and what do the lower limbs provide? What bones are part of the upper limbs?

-Most *vertebrates* also have an *appendicular skeleton* that includes the *appendages/bones that anchor the appendages* and consists of the *arms, legs, shoulder girdle, pelvic girdle* -The appendicular skeleton is *composed of the bones of the upper limbs* (which function to *grasp and manipulate objects*) and the *lower limbs* (which permit *locomotion*). It also includes the *pectoral girdle (shoulder girdle)* = that *attaches the upper limbs to the body*, and the *pelvic girdle* = that *attaches the lower limbs to the body* -Upper limbs = *humerus, ulna, radius, carpals, metacarpals, phalanges, metacarpals, phalanges* -Lower limbs = *femur, fibula, tarsals, metatarsals, phalanges* -The pectoral girdle bones provide the points of attachment of the upper limbs to the axial skeleton. The human pectoral girdle consists of the clavicle (or collarbone) in the anterior, and the scapula (or shoulder blades) in the posterior

Reception What is the first step in sensation? How do receptors get activated?

-The *first step in sensation* = *reception*, which is the *activation of sensory receptors by stimuli* such as *mechanical stimuli* (being bent or squished, for example), *chemicals*, or *temp* -The *receptor can respond to stimuli* -The *region in space where a given sensory receptor could respond to a stimulus* be it *far away/contact w/ body* is that = *receptor's receptive field* -Think for a moment about the differences in receptive fields for the different senses. For the *sense of touch* = a *stimulus must come into contact w/ body* -For the sense of hearing, a *stimulus can be a moderate distance away* (some baleen whale sounds can propagate for many kilometers) - For vision, a stimulus can be very far away; for example, the visual system perceives light from stars at enormous distances.

The ear converts air pressure waves to action potentials that are perceived as sound How do the human ear channels sound waves? What does the eustachian tube connect permitting pressure equalization? Pressure waves transmit to ? Louder sounds generate more _______ __________ What could deafness result from? (4) What is the cochlea? Where does transduction occur? What are the 3 organs in the inner ear that detect body position/movement?

-The *human ear channels sound waves*: •from the *outer ear w/ a flap-like pinna* •down the *auditory canal* •to the *eardrum* which *separates the outer ear from middle ear*, •to a *chain of bones in middle ear* (malleus, incus, and stapes), and •to the *fluid in the coiled cochlea* in the inner ear -The *Eustachian tube* connects the *pharynx to middle ear*, permitting *pressure equalization* -*Pressure waves* = transmitted *to cochlea fluid* •*bend hair cells* in the *organ of Corti against basilar membrane* and •*trigger nerve signals to brain* -*Louder sounds* generate *more action potentials* •Various pitches *stimulate diff regions of Corti organ* -*Deafness* = the *loss of hearing* + *caused by inability to detect sound* resulting from •*middle-ear infections* (could be temp), •a *ruptured eardrum*, or •*stiffening of middle-ear bones* •can also result from *damage to sensory receptors/neurons* and •is often progressive and permanent -The *cochlea* = is a *whorled structure*, like the shell of a snail, and it *contains receptors for transduction of mechanical wave into electrical signal* -Inside the cochlea, the *basilar membrane* is a *mechanical analyzer* that runs the length of the cochlea, *curling toward the cochlea's center* -The *site of transduction* = in the *organ of Corti (spiral organ)* -It is composed of *hair cells held in place above basilar membrane* like flowers projecting up from soil -In mammals, *sound waves are collected by the external cartilaginous part* of the ear called the = *pinna* then *travel to auditory canal* and cause *vibration of thin diaphragm* called the *tympanum/eardrum* = the *innermost part* of the outer ear -*Interior to tympanum* = the *middle ear* + the middle ear *holds 3 small bones* = the ossicles which transfer energy from the moving tympanum to the inner ear •*3 organs in inner ear* detect *body position/movement* -These include *3 semicircular canals* and *2 chambers* = the *utricle* and the *saccule* •All *3 structures* operate on same principle: the *bending of hairs on hair cells* •*Semicircular canals detect changes* in the *head's rate of rotation/angular movement* •The *utricle and saccule* detect the *position of the head w/ respect to gravity*

The limbic system is involved in emotions and memory What is the limbic system involved in? (3) What does it include? (2) What is memory? What part is involved in forming memories and what's involved in laying down memories?

-The *limbic system* is involved in -*emotions* such as nurturing infants and bonding -emotionally to other people, -*motivation* and *fear* -*memory* The limbic system includes *parts of thalamus and hypothalamus* and *2 partial rings* around them *formed by portions of the cerebral cortex* -*Memory* = which is *essential for learning* is the ability to *store and retrieve info* derived from experience. -The *hippocampus* is involved in both the *formation of memories + recall* -The *amygdala* is central in *laying down emotional memories* -One important structure within the limbic system is a *temporal lobe structure called the amygdala* -The two amygdala are important both for sensation of fear + recognizing fearful faces* -The cingulate gyrus helps regulate emotions and pain -*Short-term memory* as the name implies, lasts only a short time -*Long-term memory* lasts much longer and is *enhanced by rehearsal* + *posi/neg emotional states mediated by amygdala* and the *association of new data* w/ *data previously learned/stored in long-term memory* *Skill memories* (muscle memory) usually involve *motor activities that are learned by repetition without consciously remembering specific info* and include tying your shoes, riding a bicycle, or hitting a baseball.

Transduction What is the translation of a sensory signal to electrical signal What takes place at sensory receptor and changes the electrical potential? How is sensory input, such as pressure on the skin, changed to a receptor potential? (what is this type of receptor called) the stronger the stimulus, the greater the ____________ ____________ If the magnitude of depolarization is enough and what is reached, then the neuron will fire a what? What is sensory adaptation?

-The *most fundamental function of a sensory system* is the *translation of sensory signal to electrical signal* in the nervous system -This *takes place at sensory receptor*, and the *change in electrical potential produced* = is called the *receptor potential* -How is sensory input, such as pressure on the skin, changed to a receptor potential? In this example, a type of *receptor called a mechanoreceptor* = possesses *specialized membranes responding to pressure* -*Compressing/bending dendrites opens gated ion channels* in the plasma membrane *of sensory neuron*, *changing its electrical potential* -Recall that in the nervous system, a *positive change of a neuron's electrical potential* (also called the membrane potential), *depolarizes the neuron* -*Receptor potentials are graded potentials:* the magnitude of these graded (receptor) potentials *varies w/ stimulus strength* + *Changes in flow of ions* create a *graded change in membrane potential in sensory receptors* •Receptor potentials vary; the stronger the stimulus, the greater the receptor potential. -If the *magnitude of depolarization is sufficient* (that is, if membrane potential reaches a threshold), the *neuron will fire* = an *action potential* -In most cases, the correct stimulus impinging on a sensory receptor will drive membrane potential in a positive direction, although for some receptors, such as those in the visual system, this is not always the case •Repeated stimuli may lead to *sensory adaptation* = the *tendency of sensory receptors to become less sensitive* when they are stimulated *repeatedly*

Introduction of the types of Skeletal Systems What does the muscular/skeletal systems provide and allow for the body? How do the muscles work to move the body? What can affect the joints and can make movement difficult in arthritis?

-The *muscular/skeletal systems* provide *support to the body* and *allow for movement* -The *bones of skeletal system protect body's internal organs* and *support body's weight* -The *muscles* of the muscular system *contract/pull on the bones*, *allowing for movements* as diverse as *standing, walking, running, grasping* items -*Injury/disease affecting musculoskeletal system* can be very debilitating -In humans, the *most common musculoskeletal diseases* worldwide are *caused by malnutrition* -*Ailments that affect the joints* are also widespread, such as *arthritis*, which can make *movement difficult* and—in advanced cases—*completely impair mobility* -In severe cases in which the joint has suffered extensive damage, joint replacement surgery may be needed. Progress in the science of prosthesis design has resulted in the development of artificial joints, with joint replacement surgery in the hips and knees being the most common. Replacement joints for shoulders, elbows, and fingers are also available. Even with this progress, there is still room for improvement in the design of prostheses. The *state-of-the-art prostheses have limited durability* and therefore wear out quickly, particularly in young or active individuals. Current research is focused on the use of new materials, such as carbon fiber, that may make prostheses more durable.

The PNS has two functional components: What are the 2 systems of the PNS? (2) What are the divisions of the 2nd system? (3)

1. *The motor system* -*carries signals from CNS* to *skeletal muscles*, mainly in response to external stimuli, and is mostly *voluntary*. 2. *The autonomic nervous system* -*regulates internal environment* by *controlling smooth* and *cardiac muscles* and the *organs and glands* of the digestive, cardiovascular, excretory, and endocrine systems and is mostly *involuntary* -The *parasympathetic division* primes the body for activities that *gain/conserve energy* for the body. -The *sympathetic division* prepares the body for *builds for intense, energy-consuming activities* -The *enteric division* consists of networks of *neurons in the digestive tract, pancreas, gallbladder* that control *secretion and peristalsis*

The vertebrate brain develops from three anterior bulges of the neural tube + lobes What are the 3 parts of the brain? What does the forebrain have? CTHPP What does the hindbrain have? PCM What are the 4 lobes and what does each do? (hint: work your way up yourface) What areas form boundary btwn frontal and parietal lobes? What is the motor cortex? What is the somatosensory cortex? What is the cerebral cortex?

-The *vertebrate brain* evolved by the enlargement and subdivision of the *1. forebrain* = *Cerebrum* + *Diencephalon* (thalamus, hypothalamus, posterior pituitary, pineal gland) *2. midbrain* *3. hindbrain* = *Pons* + *cerebellum* + *Medulla oblongata* In the course of vertebrate evolution, the forebrain and hindbrain gradually became subdivided structurally and functionally -*Frontal lobe* = *motor cortex* and *speech* -*Parietal lobe* = *Speech* and *taste* and *reading* and somatosensory association area -*Temporal lobe* = *Smell* and *hearing* and auditory association area -*Occipital lobe* = *vision* + visual association area Two areas of known function form the boundary between the frontal and parietal lobes. -*The motor cortex* mainly *sends commands to skeletal muscles* signaling appropriate responses to sensory stimuli. -*The somatosensory cortex receives* and partially integrates *signals from touch, pain, pressure, temp receptors* throughout the body. -*The cerebral cortex 80% of BRAIN* also has centers that receive and begin *processes sensory info* concerned with *vision, hearing, taste, smell* -*Association areas* are concerned with *higher mental activities* such as *reasoning + lang* and make up most of the cerebrum. The right and left cerebral hemispheres tend to specialize in different mental tasks, a phenomenon known as lateralization. In birds and mammals, the *cerebrum is much larger* and correlates with their sophisticated behavior. The *cerebrum's outer region = the cerebral cortex*, enlarges during mammalian brain development and is *vital for perception, voluntary movement, learning* The cerebrum, the largest and most complex part of our brain, consists of *right and left cerebral* hemispheres. A thick band of *nerve fibers* called the *corpus callosum* facilitates *communication between the hemispheres* Under the corpus callosum, groups of *neurons called the basal nuclei are important in motor coordination* + control and *posture*

Human Axial Skeleton The vertebrate system provides the structural support and means of location that enable what to colonize land? All vertebrates have an axis and a __________ which consists of what 3 structures? What are the 5 parts of the vertebrate?

-The *vertebrate skeletal system* provided the *structural support* and *means of location* that *enabled tetrapods to colonize land* + support central axis of the body -All vertebrates have an axial skeleton that *supports the axis, trunk*, of the body and consists of a *skull, vertebrae, ribs* -The bones of the *skull* = *support the structures of the face* and *protect the brain*. The skull consists of 22 bones, which are divided into two categories: cranial bones and facial bones. The cranial bones are eight bones that form the cranial cavity, which encloses the brain and serves as an attachment site for the muscles of the head and neck. The eight cranial bones are the frontal bone, two parietal bones, two temporal bones, occipital bone, sphenoid bone, and the ethmoid bone. Although the bones developed separately in the embryo and fetus, in the adult, they are tightly fused with connective tissue and adjoining bones do not move -The *auditory ossicles* = of the middle ear *transmit sounds from air as vibrations* to the fluid-filled cochlea. The auditory ossicles consist of six bones: two malleus bones, two incus bones, and two stapes on each side. These are the smallest bones in the body and are unique to mammals. -Fourteen *facial bones* = form the *face, provide cavities for the sense organs* (eyes, mouth, and nose), protect the entrances to the digestive and respiratory tracts, and serve as attachment points for facial muscles. The 14 facial bones are the nasal bones, the maxillary bones, zygomatic bones, palatine, vomer, lacrimal bones, the inferior nasal conchae, and the mandible. All of these bones occur in pairs except for the mandible and the vomer. -The *vertebral column* =, or spinal column, *surrounds/protects the spinal cord, supports the head*, and acts as an *attachment point for ribs/muscles* of the back and neck (*Cervical, thoracic, lumbar (strongest/largest), sacrum, coccyx*) -*Intervertebral discs* composed of *fibrous cartilage lie btwn adjacent vertebral bodies* from the second cervical vertebra to the sacrum. Each disc is part of a joint that allows for some movement of the spine and acts as a cushion to absorb shocks from movements such as walking and running -The *thoracic cage*, also known as the ribcage, is the *skeleton of the chest*, and consists of *ribs, sternum, thoracic vertebrae, costal cartilages*. The thoracic cage encloses and protects the organs of the thoracic cavity, including the heart and lungs. -The *sternum* = or breastbone, is a *long, flat bone located at anterior of the chest*. It is formed from three bones that fuse in the adult. The ribs are 12 pairs of long, curved bones that attach to the thoracic vertebrae and curve toward the front of the body, forming the ribcage. Costal cartilages connect the anterior ends of the ribs to the sternum, with the exception of rib pairs 11 and 12, which are free-floating ribs.

Types of Neurons Are there diff types of neurons and functions? What are the 4 types of neurons?

-There are *diff types of neurons + functions* of a given neuron is intimately dependent on its structure -There is an amazing *diversity of neuron shapes/sizes* found in different parts of the nervous system (and across species) -While there are many defined neuron cell subtypes, *neurons are broadly divided into 4 types*: *unipolar, bipolar, multipolar, pseudounipolar* -*Unipolar neurons* = have only *1 structure that extends away from the soma* (insects where they stimulate muscles or glands) -*Bipolar neuron* = has *1 axon* and *1 dendrite* extending from the soma* retinal bipolar cell receives signals from photoreceptor cells that are sensitive to light and transmits these signals to ganglion cells that carry the signal to the brain -*Multipolar neurons* are the most common type of neuron. Each multipolar neuron contains *one axon and multiple dendrites*. Multipolar neurons can be found in the central nervous system (brain and spinal cord). An example of a multipolar neuron is a Purkinje cell in the cerebellum, which has many branching dendrite pseudos but only one axon. -*Pseudounipolar cells* share characteristics with both unipolar and bipolar cells. A pseudounipolar cell has a single process that extends from the soma, like a unipolar cell, but this process later branches into two distinct structures, like a bipolar cell. Most sensory neurons are pseudounipolar and have an *axon that branches into two extensions*: one connected to dendrites that receive sensory information and another that transmits this information to the spinal cord.

Glia They are known as _________________ cells. A Schwann cell is a type of _____ in the _____________ system. What does it wrap and what material? Are there more glial cells or neurons? What is MS?

-To function normally, *neurons of all vertebrates* and most invertebrates have *supporting cells* = called *glia* -*Schwann cell* = a *type of glia in the PNS*, often *wraps an axon in thick insulating material* = called the *myelin sheath* analogous to the plastic insulation that covers many electrical wires. -The *gaps btwn Schwann cells* = are called *nodes of Ranvier* an adaptation that *incr speed of signals along an axon* -This is distinctive from the PNS where a single Schwann cell provides myelin for only one axon as the entire Schwann cell surrounds the axon -*Multiplesceloris (MS)* = *AUTOIMMUNE* ; *myelin sheath is damaged*, in MS the myelin sheath is damaged *by your own immune system* (autoimmune- difficult to control) -While *glia are the supporting cast* of the nervous system, the number of *glial cells outnumbers the neurons* by a factor of ten. Neurons would be unable to function without the vital roles that are fulfilled by these glial cells. Glia guide developing neurons to their destinations, buffer ions and chemicals that would otherwise harm neurons, and provide myelin sheaths around axons. Scientists have recently discovered that they also play a role in responding to nerve activity and modulating communication between nerve cells. When glia do not function properly, the result can be disastrous—most brain tumors are caused by mutations in glia.

Introduction to Nervous System What does the visual system do? What does the motor system do? What does the prefrontal cortex do? What is the nervous system? 3 functions? What is depression? What common drug treats depression? And what does the drug do in the brain?

-When you're reading this book, your *nervous system* is *performing several functions simultaneously* -The *visual system* is *processing what is seen on the page*; -The *motor system* is *controlling the turn of the pages (or click of the mouse)*; -The *prefrontal cortex maintains attention* -Even fundamental functions, like *breathing and regulation of body temp*, are *controlled by nervous system* -A *nervous system* is an *organism's control center*: it *processes sensory info from outside (and inside)* the body and *controls all behaviors—from eating to sleeping* to finding a mate •The nervous system 1.*receives sensory info* 2. *integrates it*, and 3. *commands app responses*, either an action or no action. -*More than 20 mil Americans* = are *affected by depression* in a given year -*Depression* = a *psychiatric disorder* characterized by *persistent sadness*, *loss of interest* in pleasurable activities, *changes in weight/sleep* patterns, *diminished energy*, and *suicidal thoughts* over a continuous period. -*Drugs* that treat medically diagnosed *depression*, *antidepressants*, are the third most *commonly prescribed* class of drugs in the United States -The *most widely prescribed antidepressants*, selective serotonin reuptake inhibitors *(SSRIs)*, *block reabsorption of particular mood-regulating* chemical called *serotonin into brain cells* However, *SSRIs* are most effective for the *severely depressed* and offer little or no benefit to the moderately depressed

Action Potential Transmission btwn signals is carried by a chemical called? A transmission of a signal in a neuron is carried by a brief reversal of resting potential = ? Where do the neurotransmitters bind to? At excitatory synapses, what does the opening allow? AN action potential is simply a change in __________ __________ What does it mean by action potentials being self-propagated?

A stimulus is any factor that causes a nerve signal to be generated. -A *neuron gets input from other neurons* and, if this input is strong enough, *sends the signal to downstream neurons* -*Transmission of signal btwn neurons is carried by* = a chemical called *neurotransmitter* -*Transmission of a signal IN a neuron* (from dendrite to axon terminal) is carried by a *brief reversal of resting membrane potential* = called an *action potential* -When *neurotransmitter molecules bind to receptors* located on a neuron's dendrites, ion channels open -At *excitatory synapses*, this *opening allows posi ions (Na+) to enter the neuron* and *results in DEPOLARIZATION* of the membrane—a *decr in diff in voltage btwn the inside/outside of the neuron* - A *nerve signal* called an *action potential*, a *change in the membrane voltage*, that transmits a nerve signal along an axon. The rapid *flip-flop of membrane potential is bc of rapid movements of ions across the membrane* at Na+ and K+ voltage-gated channels, that open and close in response to stimuli. -*Action potentials* are *self-propagated + one-way chain* reaction along a neuron and *all-or-none events* The frequency of action potentials (but not their strength) changes with the strength of the stimulus. Five steps to formation of action potential *1.* : Voltage-gated Na+ and K+ channels are closed; resting potential is maintained by ungated channels. A *stimulus from a sensory cell/another neuron* causes the *target cell depolarizes towards the threshold* potential *2.* If the *threshold of excitation is reached* = all *Na+ channels open* + *membrane depolarizes*. Once the sodium channels open, the neuron completely depolarizes to a membrane potential of about +40 mV. Action potentials are considered an "all-or nothing" event, in that, once the threshold potential is reached, the neuron always completely depolarizes. *3.* At the *peak action potential*, *REPOLARIZATION* = *K+ channels open* and *K+ begin to leave* the cell. At the same time, Na+ channels close once depolarization is complete, the cell must now "reset" its membrane voltage back to the resting potential. To accomplish this, the Na+ channels close and cannot be opened. This begins the neuron's refractory period, in which its sodium channels will not open. As K+ ions leave the cell, *the membrane potential once again becomes negative* *4.* The *membrane becomes hyperpolarized as K+ ions leave the cell* in that the *membrane potential becomes more negative than cell's normal resting potential*. At this point, the sodium channels will return to their resting state, meaning they are ready to open again if the membrane potential again exceeds the threshold potential *5.* The *K+ channels close* and the *Na+/K+ transporter restores resting potential*. Eventually the extra K+ ions diffuse out of the cell through the potassium leakage channels, bringing the cell from its hyperpolarized state, back to its resting membrane potential.

The human female reproductive system includes the ovaries and structures that deliver gametes Both sexes have a set of gonads which are what? Ovaries contain what that can care/nurture/develop the eggs What are oviducts and what do they collect after ovulation? They are the typical site of what process? What does a uterus do? It is the site of what? What is the vulva? What is the labia minora and majora? What is the clitoris?

Both *sexes in humans* have -a set of *gonads* = the *organs produce gametes*, -*ducts* = that *store/deliver gametes*, and -*structures* that *allow mating* *Ovaries* contain *follicles* that -carry, develop and *nurture eggs* and -produce the *female sex hormone estrogen* An *immature egg* is *ejected from follicle* = in a process called *ovulation* about *every 28 days* -*After ovulation*, what *remnants of follicle grows in the ovary* - to form a *solid mass* called the *corpus luteum* which secretes *additional estrogen-progesterone* *Oviducts* (fallopian tubes) -collect *eggs after ovulation* -are the typical *site of fertilization* and -convey *TRANSPORT eggs to uterus* where a *fertilized egg develops* The oviducts, or *fallopian tubes extend from uterus* in the lower abdominal cavity *to the ovaries*, but they are *not in contact w/ ovaries* The lateral ends of the oviducts flare out into a trumpet-like structure and have a fringe of finger-like projections called fimbriae *Uterus* -has a *thick muscular wall* -is *lined by endometrium*, richly *supplied w/ blood vessels* -*SUPPORT DEVELOPING EMBRYO* -is the actual *site of pregnancy* and -opens in *to vagina thru cervix* The uterus is a structure about the size of a woman's fist. This is lined with an endometrium rich in blood vessels and mucus glands. The uterus supports the developing embryo and fetus during gestation. The thickest portion of the wall of the uterus is made of smooth muscle. Contractions of the smooth muscle in the uterus aid in passing the baby through the vagina during labor. A portion of the lining of the uterus sloughs off during each menstrual period, and then builds up again in preparation for implantation. Part of the uterus, called the cervix, protrudes into the top of the vagina. The cervix functions as the birth canal -The term *embryo* = is used for the *stage in development from first division of zygote till body structures appear*, about the *9th week* in humans. -From the *9th week till birth* = a *developing human* is called a *fetus* An *ectopic pregnancy* = -results when the *embryo implants somewhere other than uterus* and -occurs in about *1% of pregnancies* The *female reproductive anatomy* consists of -the *vulva* = the collective term for the *external female genitalia* -a *pair of slender skin folds* = the *labia minora* which border the openings, and covers vestibule The labia minora are thin folds of tissue centrally located within the labia majora. These labia protect the openings to the vagina and urethra. The mons pubis and the anterior portion of the labia majora become covered with hair during adolescence; the labia minora is hairless. The greater vestibular glands are found at the sides of the vaginal opening and provide lubrication during intercourse. -a *pair of thick, fatty ridges* = the *labia majora* which *protect the vaginal opening* and covers labia minora The labia majora are a pair of elongated folds of tissue that run posterior from the mons pubis and enclose the other components of the vulva. The labia majora derive from the same tissue that produces the scrotum in a male -Until sexual intercourse or vigorous physical activity ruptures it, a *thin piece of tissue* = called the *hymen* partly *covers vaginal opening* -The *clitoris* = sensory organ consists of a *short shaft supporting rounded glans*/*head covered by small hood of skin* = called the *prepuce* The clitoris is a structure with erectile tissue that contains a large number of sensory nerves and serves as a source of stimulation during intercourse.

The formation of sperm and egg cells requires meiosis

Both sperm and egg are haploid (n) cells that develop by meiosis from diploid (2n) cells in the gonads. There are significant differences in gametogenesis, the formation of gametes, between human males and females. -*Spermatogenesis* occurs in *seminiferous tubules*. 1. *Prophase I* is diploid and *Primary spermatocytes* are *formed by mitosis* and *divide by meiosis I* = to produce *secondary spermatocytes* 2. *Secondary spermatocytes divide by meiosis II* (two n's) to *produce round spermatids*, and spermatids *mature/differentiate into elongate sperm* (four n's) -No stoppage in production of sperm like in females (menopause) -*Oogenesis* = begins *before birth* when a diploid cell in each developing follicle begins meiosis. About every 28 days, -*Prophase I* of *follicle stimulating hormone (FSH)* from the pituitary *stimulates* one of the *dormant follicles to develop*, rested for a long time 1. *one primary oocyte resumes meiosis*, when *meiosis I is complete* = *puberty* (2n) 2. *Metaphase I* of Meiosis II = a *secondary oocyte* arrested at metaphase of meiosis II is *ovulated*, and meiosis of the ovum is *completed after fertilization*. Reproductive organs are under the influence of hormones, if ovaries stop doing what they do = no eggs/hormones Oogenesis and spermatogenesis are alike in that both *produce haploid gametes but diff* in that *oogenesis prod only 1 mature egg* and *polar bodies that degenerate* spermatogenesis produces four mature gametes, and -*spermatogenesis occurs at puberty until death*, while the mitotic divisions of *oogenesis is before birth* and the production of mature gametes *ceases at menopause*

Characteristics of muscle fiber affect athletic performance What 3 categories can muscle fibers be classified as? What kinds of fibers are used in Cellular Respiration? Fermentation? Mitochondria/capillaries?

Depending on the pathway they use to generate ATP, *muscle fibers* can be classified as -*slow* -*intermediate* or -*fast* Most muscles have a combination of fiber types, which can be affected by exercise. -*Speed of contraction* = *SLOW fibers (slow)* + *FAST fibers (fast)* -*Rate of fatigue* = *SLOW fibers (slow fatigue)*, *FAST fibers (fatigue rapidly)* -*Primary pathway for making ATP* = *SLOW fibers (CELL resp)*, *FAST fibers (fermentation)* -*Myoglobin content* = *SLOW fibers (high)*, *FAST fibers (low)* -*Mitochondria and capilarries* = *SLOW fibers (high)*, *FAST fibers (low)* The fibers that make up a muscle are not all alike. The contractions of "fast-twitch" fibers are rapid and powerful, but the fibers fatigue quickly. "Slow-twitch" fibers can sustain repeated contractions and are slow to fatigue, but their contractions are less forceful. A third fiber type, which has some characteristics of both slow and fast fibers, is also abundant in human muscle. Most of the features associated with fiber type reflect the pathway(s) the fiber preferentially uses to generate ATP from energy-rich molecules. Each muscle typically has a mixture of fiber types, broadly correlated to the action it performs. ACTN3 encodes α-actinin-3, a protein that is a major part of the Z line in fast-twitch muscle fibers, where it anchors thin filaments from adjacent sarcomeres. In a study published in 2003, a group of researchers hypothesized that variation in ACTN3 is a factor in athletic performance. To test their hypothesis, the researchers compared the ACTN3 genotypes of 301 elite athletes with the genotypes of a control group of 436 nonathletes. The results are shown in Table 30.12B. More than 90% of power athletes, whose successful performance depends on fast-twitch fibers, had the ability to produce α-actinin-3 (genotype RR or Rr). A 2011 meta-analysis of more than a dozen other such studies supports the hypothesis that possessing an R allele, especially with an RR genotype, is more common among power athletes. Thus, a genetic test for ACTN3 genotype offers one piece of information about athletic potential. However, physical prowess is influenced by many genes in addition to ACTN3 and by many other factors.

The knee-jerk reflex 5 steps Where does the sensory neuron (and ganglion) go to? Where does the interneuron go? The motor neuron? What do the muscles need to do to respond? What is a reflex?

a variant of the stretch reflex in which stretching of the tendon beneath the knee leads to an upward kick of the leg 1. *Sensory receptor* of hammer hitting the tendon 2. *Sensory Neuron* + ganglion to SPINAL CORD to BRAIN 3. *Interneuron* from BRAIN to SPINAL CORD 4. *Motorneuron* from SPINAL CORD to MUSCLE 5. *Quadriceps contract* while the *flexor relaxes* Reflexes: *motor responses to any stimuli*, *life-saving*, we do somatic reflexes which test the integration of spinal cord

What causes motion sickness? Motion sickness could be cause by conflicting signals where ? (2) Who is it especially a problem for? How can it be reduced? (4)

•*Motion sickness* may be *caused by conflicting signals* between the *inner ear/eyes* •*Motion sickness* can be a *severe prob for astronauts* -Motion sickness may be *reduced by* •*closing eyes*, •*limiting head movements*, •*focusing* on a *stable horizon*, or •*sedatives* such as Dramamine.

Anatomy of the Eye What are two major types of image-forming structures that have evolved? What structure has several thousand light detectors called ommatidia? In single-lens eyes light enters the front center of the eye through an opening called This pupil is controlled by another structure called the ________ that focuses on the retina which consists of many ____________________ cells. The center of focus is what and it is responsible for acute vision? The photoreceptive cells are where what happens? What is the cornea? What is the iris?

•*Two major types of image-forming structures* have evolved. 1. *Compound eyes*, found in *insects and crustaceans*, •consist of up to *several thousand light detectors* = called *ommatidia*, •*function as acute motion detectors*, and •usually *provide excellent color vision* 2.In *single-lens eyes*, *light enters front center of eye through small opening* =*pupil*, controlled by an *iris* = *passes thru single lens*, and is *focused onto retina*, which consists of *many photoreceptor cells* •The *center of focus* = is the *fovea*, where *photoreceptor cells are highly concentrated* + responsible for *acute vision* •Single-lens eyes evolved independently in vertebrates and invertebrates, *originating from diff tissues that were repurposed to become eyes* -The *photoreceptive cells* of the eye, where *transduction of light to nervous impulses occurs*, are located in the = *retina* on the inner surface of the back of the eye -But *light does not impinge on the retina* unaltered -It *passes thru other layers that process* it so that it *can be interpreted by the retina* -The *cornea* = the *front transparent layer of the eye*, and the *crystalline lens* = a *transparent convex structure behind the cornea*, both *refract (bend) light to focus image on the retina* -The *iris* = which is *conspicuous as the colored part* of the eye, is a *circular muscular ring lying btwn lens and cornea* that *regulates the light entering the eye* -In conditions of high ambient light, the iris contracts, reducing the size of the pupil at its center. In conditions of low light, the iris relaxes and the pupil enlarges.

The model for magnetic sensory reception is incomplete What is magnetoreception? What are three major hypotheses that exist to explain the detection step in sensory reception as it relates to magnetoreception?

•Although *steps in human sensory reception are clear*/understood, those in *other animals w/ unique senses are less clear* •For sea turtles sensing Earth's magnetic field, the *first step, detection*, relates to magnetic sense = *(magnetoreception)* is essentially unknown. Even the location of the magnetic sensory cells is obscure •Evidence suggests that there is *not just one way animals detect magnetic field* to navigate. *Three major hypotheses* exist to explain the detection step in sensory reception as it relates to magnetoreception. •One hypothesis proposes that *electrical fluctuations*, influenced by Earth's magnetic field, are *detected by sensory cells* •The other two hypotheses suggest that *variations in magnetic field affect biochemical reactions* or the *alignment of minerals inside sensory cells* •As is often the case in science, the different hypotheses need not be mutually exclusive. •The strong magnetic mineral magnetite, which is used in compass needles, has been found in some animals with a magnetic sense, such as loggerhead sea turtles. •Yet finding individual cells that contain magnetite has been challenging because a magnetite crystal is tiny (about 50 nm in diameter) •In 2012, scientists dissociated cells from the nasal tissue of rainbow trout, suspended the cells in fluid, and subjected the cells to a rotating magnetic field. •The spinning cells were separated and further examined by microscopy. •Examination suggested that magnetite crystals anchor to the plasma membrane. •Scientists hypothesize that mechanical pressure exerted by the magnetite crystals on the plasma membrane might cause ion channels to open, converting the pressure into a receptor potential capable of stimulating sensory neuron action potentials.

Taste and odor receptors detect chemicals present in solution or air What are the taste receptors and what 5 taste sensations do they produce?

•Taste and smell depend on chemoreceptors that detect specific chemicals in the environment. •Chemoreceptors in taste buds detect molecules in solution, and those lining the nasal cavity detect airborne molecules. •Taste and smell interact. Much of what we taste is really smell. •*Taste receptors* = are located *in taste buds on the tongue* and produce five taste sensations: 1.*sweet*, 2. *salty*, 3. *sour*, 4. *bitter*, and 5. *umami* (the savory flavor of *meats and cheeses*) •About 25% of humans are "supertasters," with up to three times the sensitivity to bitter. •Supertasters are more likely to •avoid spinach, broccoli, cabbage, coffee, and alcoholic beverages and •have a higher risk of colon cancer and some other serious health problems.

Outer + Inner Surface of the Eye What is the sclera and what does it turn into in the front of your eye? What is the choroid and what does it form that gives the eye its color? What 2 chambers do the lens and ciliary body divide the eye into? What do the chambers do? What is the conjunctiva?

•The *outer surface* of the human eyeball is a *tough, whitish layer of connective tissue* = called the *sclera* •At the *front of the eye*, the *sclera becomes transparent cornea*, which *lets light in*to the eye and also helps *focus light* •The *sclera surrounds a pigmented layer* = called the *choroid* -The *anterior choroid* forms the *iris*, which gives the eye its color •The *lens + ciliary body divide the eye into 2 fluid-filled chambers* 1. The *LARGE CHAMBER behind the lens* is *filled w/ a jellylike vitreous humor* 2. The *SMALLER CHAMBER* in *front of lens* contains the *thinner aqueous humor* -These humors: •help *maintain shape of eyeball* and •*circulate nutrients/oxygen to lens, iris, cornea* bc they have no blood and need support •The *conjunctiva* = *lines inner surface of eyelids* and *folds back over white of the eye* (but not the cornea). •*Conjunctivitis* = is an *inflammation of the conjuctiva by bacteria/virus* •A *gland above eye secretes tears* that *clean* and *moisten* the eye

The human retina contains two types of photoreceptors: rods and cones What are rods? What are cones?

•The human retina contains two types of photoreceptors. 1.Rods •can detect shades of gray in dim light and •contain the visual pigment rhodopsin, which can absorb dim light. 2.Cones •allow us to see color in bright light and •contain the visual pigment photopsin, which absorbs bright-colored light. •When rhodopsin and photopsin absorb light, they change chemically, and the change alters the permeability of the cell's membrane. •The resulting receptor potential triggers a change in the release of neurotransmitter from the synaptic terminals. •This release initiates a complex integration process in the retina.

Visual Acuity What is visual acuity? What are the 3 vision problems/conditions?

•Visual acuity is the *ability of the eyes to distinguish fine detail* •Visual acuity is measured by reading standardized eye charts from a distance of 20 feet. •The ability to read accurately at 20 feet is called 20/20 vision. •Three vision problems are common. 1.*Nearsightedness* is the *inability to focus on distant* objects, usually caused by an eyeball that is too long. 2. *Farsightedness* is the *inability to focus on close objects*, usually caused by an eyeball that is too short. 3. *Astigmatism* is *blurred vision* caused by a misshapen lens or cornea. •Corrective lenses can bend light rays to compensate for each of these problems.

Specialized sensory receptors detect five categories of stimuli What does a painreceptor detect? What do thermoreceptors detect? What do mechanoreceptors respond to? What do chemoreceptors include? What do electromagnetic receptors respond to?

•We can group animal sensory receptors into general categories, based on the type of signals to which they respond. 1. *Pain receptors* detect *dangerous stimuli* including *high heat + pressure* 2. *Thermoreceptors* detect *heat/cold* -In addition to Krause end bulbs that detect cold and Ruffini endings that detect warmth, there are *diff types of cold receptors on free nerve endings*: thermoreceptors, located in the *dermis, skeletal muscles, liver, hypothalamus* that are *activated by diff temps* -Their pathways into the brain run from the spinal cord through the thalamus to the primary somatosensory cortex. Warmth and cold info from the face travels through a cranial nerve to the brain. You know from experience that a tolerably cold/hot stimulus can quickly progress to a much more intense stimulus that is no longer tolerable. Any stimulus that is too intense can be perceived as pain because temperature sensations are conducted along the same pathways that carry pain sensations 3. *Mechanoreceptors* respond to *mechanical energy* such as •*touch* and *pressure* •*stretching* •*motion* and *sound* 4. *Chemoreceptors* include *sensory receptors in nose/taste buds* and respond to chemicals. 5. *Electromagnetic receptors* respond to •*electricity*, •*magnetism*, or •various *wavelengths of light*

Sensory receptors convert stimulus energy to action potentials When a sugar molecule binds to a sweet receptor, the binding triggers a ___________ _______________ Some ion channels do what then and what is it called _______________ potential Then this potential passes into what system?

•When a *sensory receptor cell in a taste bud detects sugar molecules*, 1. *sugar molecules arrive* at the *taste bud* 2. *sugar molecules bind to sweet receptors*, specific *protein molecules embed in plasma membrane* of a *taste receptor cell* and 3. the *binding triggers a signal transduction pathway* that causes 4. some *ion channels in membrane to close/others to open*. These *changes in flow of ions* create a *graded change in membrane potential* = called a *receptor potential* 5. Once a *stimulus converted to a receptor potential* the *receptor potential results in signals passing into the CNS* 6. The graph shows the *rate at which the sensory neuron sends action potentials* when the *taste receptor is/is not detecting any sugar*