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IB Biology 22-24 > Topic 11: Animal Physiology > Flashcards

Topic 11: Animal Physiology Flashcards

1
Q

Outline function of biceps.

A

Raise lower arm

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2
Q

Outline function of cartilage.

A

Reduces friction, absorbs shock

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3
Q

Outline function of distal convoluted tubule.

A

selective reabsorption of glucose/minerals/amino acids by active transport

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4
Q

Explain the role of the medulla and the collecting duct of the kidney in the maintenance of the water balance in blood. [3]

A
  • collecting duct has aquaporins
  • high solute concentration of medulla
  • reabsorption of water allows excretion of concentrated urine
  • secretion of ADH increases permeability of collecting duct to water
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5
Q

Outline how the skeletal muscle contracts. [6]

A
  • calcium ions released from sarcoplasmic reticulum
  • exposes myosin binding sites on actin
  • cross-bridges form between actin and myosin
  • ATP provides energy
  • for actin filaments to slide over myosin filaments
  • ATP provides energy to release myosin from binding sites
  • action repeated further along the molecule
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6
Q

Explain the role of the kidney in maintaining water balance in humans. [9]

A
  • osmoregulation
  • water passed into kidney tubules through ultrafiltration
  • water reabsorbed in PCT
  • water reabsorbed into blood from descending loop of Henle
  • osmosis
  • transport of salts into medulla of kidney
  • changes salt conc, water is reabsorbed
  • ADH releases into blood when water is required
  • more reabsorption of water from the collecting duct
  • causes concentrated urine
  • urine conc. depends on the body’s needs for water
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7
Q

Explain how the structure of the nephron and its associated blood vessels enable the kidney to carry out its functions. [8]

A
  • osmoregulation
  • ultrafiltration in the glomerulus
  • basement membrane filters, prevents loss of proteins
  • selective reabsorption of glucose in PCT
  • water reabsorbed in descending loop of henle
  • active transport of sodium ions out of ascending limb
  • impermeable to water
  • water reabsorbed in collecting duct
  • collecting duct permeability depends on ADH
  • osmoregulation by varying the amount of water reabsorbed
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8
Q

Describe the role of ADH in human osmoregulation.

A
  • secreted when blood plasma concentration is hypertonic/water content too low
  • makes walls of collecting duct more permeable to water
  • more aquaporins in membrane
  • more water reabsorbed from filtrate
  • small volume of concentrated urine excreted
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9
Q

Explain the role of the nephron in maintaining the water balance of the blood in the human body. [8]

A
  • ultrafiltration in the glomerulus produces large volumes of filtrate
  • 80% of water absorbed in PCT
  • water reabsorbed from filtrate in descending loop of henle
  • pituitary gland secretes ADH if blood solute conc too high
  • makes collecting duct more permeable to water
  • moves aquaporins into membranes
  • more water reabsorbed from filtrate
  • small volume of urine with high conc excreted
  • water reabsorption in collecting duct due to high solute conc of medulla
  • active transport of Na+ ions from filtrate in ascending limb of loop of Henle
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10
Q

Outline what is meant by homeostasis. [4]

A
  • Maintaining a constant internal environment
  • with narrow limits
  • e.g. blood temp/pH
  • levels monitored internally
  • negative feedback mechanisms
  • involves hormonal/nervous control
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11
Q

Explain the processes occurring in the kidney that contribute to osmoregulation. [8]

A
  • osmoregulation is the maintenance of water balance
  • loop of henle creates hypertonic conditions in the medulla
  • water reabsorbed as filtrate passes through collecting duct
  • monitored by hypothalamus
  • controls secretion of ADH
  • ADH released when blood solute conc too high
  • makes collecting duct more permeable to water
  • due to more aquaporins
  • more water reabsorbed
  • small volume of concentrated urine produced
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12
Q

Blood is a liquid tissue containing glucose, urea, plasma proteins and other components. List the other components of blood. [5]

A
  • plasma
  • dissolved gases
  • red/white blood cells
  • hormones
  • lymphocytes/phagocytes
  • platelets
  • amino acids
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13
Q

Explain the role of ATP in muscle contraction. [2]

A
  • ATP binds to myosin heads
  • ATP breaks cross-bridges
  • energy released when ATP forms ADP and phosphate
  • myosin heads reset
  • actin slides over myosin
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14
Q

Describe how skeletal muscle contracts. [3]

A
  • action potential arrives at neuromuscular junction
  • release of calcium ions from the sarcoplasmic reticulum
  • calcium binds to troponin, exposes actin to form cross-bridges
  • heads push actin filament towards sarcomere center
  • use of ATP to break cross-bridges
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15
Q

Explain how the kidney helps to retain useful substances in the blood and eliminate substances which the body does not need. [8]

A
  • ultrafiltration in the glomerulus
  • basement membrane acts as filter
  • prevents large molecules (proteins) from passing
  • filtered substances pass to bowman’s capsule
  • to PCT
  • selective reabsorption
  • all glucose reabsorbed
  • most water reabsorbed
  • area of high solute conc surrounds loop of henle
  • ions exchanged between filtrate and blood in DCT
  • collecting duct has role in osmoregulation
  • ADH regulates amount of water reabsorbed
  • substances not reabsorbed are eliminated as urine
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16
Q

Describe the production of semen. [5]

A
  • sperm produced by meiosis
  • in testis / seminiferous tubules
  • sperm stored in the epididymis
  • sperm can swim
  • seminal vesicles add fluid
  • seminal vesicles rich in fructose
  • prostate glands add fluid
  • fluid rich in proteolytic enzymes (protease)
  • semen contains alkaline substances
  • neutralizes the acidic environment of the vagina
17
Q

Explain the structure and function of the placenta. [8]

A
  • disc-shaped
  • connected to fetus by umbilical cord
  • placenta is embryonic and maternal tissue
  • placental villi increases SA
  • fetal capillaries in placenta
  • inter-villous spaces through which mother’s blood flows
  • small distance between fetus and maternal blood
  • transfer of nutrients/glucose from mother to fetus
  • transfer of oxygen from mother to fetus
  • transfer of antibodies from mother to fetus
  • transfer of waste products/CO2 from fetus to mother
  • placenta secretes progesterone and oestrogen
18
Q

Outline the hormonal control of birth. [4]

A
  • at 38-40 weeks of pregnancy fetus produces oestrogen
  • decreases progesterone production
  • removes inhibition of oxytocin secretion
  • oxytocin released by the pituitary gland
  • oxytocin stimulates uterine contraction
  • cervix dilates and widens
  • increase in oxytocin increases the rate of contractions
  • positive feedback loop
19
Q

Describe the process of fertilization in humans. [6]

A
  • sperm breaks through follicle cells
  • triggers acrosome reaction
  • proteases released
  • digests zona pellucida
  • plasma membranes of egg and sperm fuse
  • sperm nucleus enters egg
  • cortical reaction
  • hardens glycoproteins in zona pellucida
  • prevents polyspermy
20
Q

Explain how the structure and function of the placenta help to maintain pregnancy. [8]

A
  • disc-shape organ that attaches to uterus
  • connected to the fetus by the umbilical cord;
  • produces hormones/HCG that maintain pregnancy;
  • estrogen and progesterone maintain uterine lining;
  • nutrients/oxygen from mother’s blood transferred to fetal blood;
  • antibodies from mother’s blood transferred to fetal blood (through umbilical vein);
  • waste products transferred from fetal blood to maternal blood (through umbilical artery);
  • embryonic tissue grows into the uterine wall;
  • placental/chorionic villi increase the surface area’
  • fetal capillaries in placenta
  • inter-villous spaces through which mother’s blood flows;
  • small distance between fetal and mother’s blood
21
Q

Outline the role of hormones in the menstrual cycle. [6]

A
  • LH and FSH are pituitary hormones
  • FSH promotes the development of follicles
  • follicles produce oestrogen
  • oestrogen repairs and grows uterine wall
  • oestrogen causes negative feedback of FSH
  • oestrogen stimulates LH production
  • LH stimulates the development of the corpus luteum
  • corpus luteum secretes progesterone
  • progesterone maintains uterine wall
  • progesterone inhibits FSH/LH
  • lowered level of progesterone (due to degeneration of corpus luteum) leads to menstruation
22
Q

Draw a labelled diagram of a mature sperm cell. [4]

A
  • head and midpiece/mid-section/body;
  • tail/flagellum; (at least four times length of the head and containing fibres)
  • acrosome; (shown as distinct structure near front of head)
  • nucleus; (occupying more than half the width or length of head)
  • mitochondria; (as repetitive structures inside membrane of mid piece)
  • centriole; (between head and midpiece)
  • (plasma) membrane; (shown as single line covering whole cell)
23
Q

Describe the functioning of immunoglobulins. [3]

A
  • function as antibodies
  • variety of binding sites
  • specific to antigens on pathogens
  • attracts phagocytes to engulf the pathogen
  • agglutination
24
Q

Outline how antibiotics offer protection from certain forms of infectious disease. [4]

A
  • inhibit the growth of bacteria
  • bacteria processes blocked but not in eukaryotes
  • block metabolic pathways (e.g. DNA replication/transcription/translation)
  • do not protect against viruses (non-living)
  • antibiotics fail to protect if bacteria are resistant
  • used in animals/humans
25
Q

Outline the role of hormones in the process of birth in humans. [4]

A
  • level of progesterone falls before birth
  • oxytocin secreted
  • from pituitary
  • stimulates uterine contractions
  • contractions stimulate more release of oxytocin
  • positive feedback loop
26
Q

Outline the processes involved in oogenesis within the human ovary. [8]

A
  • process where female gametes are produced
  • begins in fetal development
  • large number of cells formed by mitosis
  • cells grow, become primary oocytes
  • begin first mitotic division, stop in prophase I
  • until puberty
  • some follicles develop each month in response to FSH
  • primary oocyte completes first meiotic division
  • forms two cells of unequal sizes (unequal distribution of cytoplasm)
  • creates polar body
  • polar body degenerates
  • secondary oocytes proceeds to meiosis II
  • stops at prophase II
  • meiosis II completed if cell is fertilized
  • ovum and second polar body formed
27
Q

Discuss the ethical issues surrounding IVF. [6]

A

pros

  • chance for infertile couples to have children
  • genetic screening of embryos reduces suffering from genetic diseases
  • spare embryos safely stored for future pregnancies

cons

  • IVF is expensive, not equally accessible
  • cultural/religious objections
  • lead to gender choice
  • lead to unwanted pregnancies with associated risks
  • inherited forms of infertility may be passed on to children
28
Q

Discuss the cause, transmission and social implications of AIDS. [8]

A

causes

  • AIDs caused by HIV
  • penetrates T lymphocytes
  • glycoprotein and cell receptors involved
  • reverse transcriptase enables DNA to be produced from viral RNA
  • number of lymphocytes reduced over the years
  • results in lower immunity
  • other illnesses develop

transmission

  • HIV transmitted through sexual contact/breastfeeding
  • minority of individuals have no cell receptors and do not develop AIDS
  • condoms/latex barriers act as protection from transmission through sexual contact

social implications

  • expensive treatment
  • discrimination
  • economic consequences
  • traditions/beliefs/culture
29
Q

Coughing to clear the airways is accomplished by muscle contractions. Explain muscle contraction. [8]

A
  • myofibrils in muscle cells
  • sarcomeres as the repeating units in myofibrils
  • actin and myosin as overlapping protein filaments
  • myosin (thick) actin (thin)
  • nerve impulses stimulate contraction
  • calcium ions released from sarcoplasmic reticulum and bind to troponin
  • exposes actin binding sites
  • myosin heads form cross-bridges with actin
  • ATP breaks cross-bridges, causes movement of myosin heads
  • myosin heads change angle
  • myosin filaments pull actin towards centre
  • sarcomeres shorten during contraction
30
Q

All parts of the body change the composition of the blood. Explain how the nephron changes the composition of blood. [7]

A
  • higher nitrogen/urea when blood enters bowman’s capsule
  • small soluble molecules/glucose/nutrients/ions removed from blood
  • through ultrafiltration
  • large molecules/proteins/blood cells remain in blood
  • filtrate passes through nephron, water reabsorbed via osmosis
  • selective reabsorption of glucose/nutrients in DCT via active transport
  • sodium ions pumped into medulla in loop of Henle
  • high sodium gradient enhances water reabsorption
  • permeability of collecting duct dependent on ADH
31
Q

Compare the processes of spermatogenesis and oogenesis. [8]

A

common

  • produce haploid cells/mature sex gametes
  • involve mitosis and meiosis
  • cell growth before meiosis
  • differentiation to produce specialized gametes

differences

  • where: ovaries; testes
  • when: development of embryo; puberty
  • breaks: prophase I/prophase II/metaphase I; no breaks
  • cytokinesis: split unequally, equal
  • number of gametes per meiosis: one cell/egg, some polar bodies; four sperm
  • number of gametes released: one per menstrual cycle; millions at a time
  • timing of release: at ovulation; during intercourse
  • if gametogenesis stops: menstrual pause; goes on until death
32
Q

Describe the consequences of the potential overproduction of offspring. [5]

A
  • more offspring than the environment can support
  • increased mortality
  • competition for resources
  • better adapted more likely to survive
  • better adapted pass on advantageous alleles
  • natural selection leads to evolution
33
Q

Draw a labelled diagram of a mature human egg. [5]

A
  • haploid nucleus
  • cytoplasm
  • centrioles
  • cortical granules
  • plasma membrane
  • zona pellucida
  • follicle cells
  • polar body (outside the egg cell)
  • shown as 0.1mm
34
Q

Draw a labelled diagram to show the structure of a sarcomere. [5]

A
  • sarcomere labeled between Z lines
  • Z lines at the ends
  • actin as thin filaments attached to Z lines
  • myosin as thick filaments
  • myosin heads on both sides of myosin filaments
  • light band (only actin) dark band (actin and myosin)
35
Q

Explain the process of ultrafiltration. [3]

A
  • blood in glomerulus under high pressure due to the difference in diameter of arterioles
  • fluid plasma and small molecules forced into bowman’s capsule
  • prevents large molecules from passing through
36
Q

Explain the principles of vaccination. [9]

A
  • weakened/attenuated form of a pathogen
  • introduced to patient
  • pathogen stimulates specific immune response (primary)
  • antigens stimulate T-cells
  • stimulate cloning of B-cells
  • develops memory cells
  • that produce specific antibodies
  • production of antibodies upon second exposure is much faster
  • secondary response
  • may need booster shots to maintain immunity
  • example of artificial immunity
37
Q

Describe the process of spermatogenesis in humans. [6]

A
  • spermatogonia undergoes mitosis to keep a supply of germinal cells
  • spermatogonia grow larger to become primary spermatocytes
  • primary spermatocytes go through meiosis I
  • forms secondary spermatocytes
  • secondary spermatocytes go through meiosis II
  • to produce spermatids
  • spermatids differentiate (grow tail, reduce cytoplasm)
  • associated with Sertoli cells
  • sperm detaches from Sertoli cells, enter lumen of seminiferous tubule
  • testosterone stimulates sperm production
38
Q

ADH is a peptide hormone produced in the hypothalamus. Explain its action in the human body. [8]

A
  • ADH plays a role in osmoregulation (regulating blood solute concentration)
  • acts on the collecting duct
  • acts in the DCT
  • hypothalamus detects solute concentration
  • if blood solution concentration is too high, pituitary releases ADH
  • ADH stimulates insertion of aquaporins, increase permeability of collecting duct
  • water moves by osmosis, reabsorbed into blood
  • small volume of concentrated urine produced
  • negative feedback
  • if low blood solute concentration, no ADH released
  • permeability of collecting duct decreases
  • large volume of dilute urine produced
39
Q

Describe the genetic and hormonal control of male sexual characteristics in a human. [3]

A
  • male if (X and) Y chromosomes present
  • gene on Y chromosome (SRY) promotes development of testes
  • testes secrete testosterone
  • testosterone stimulates sperm production/spermatogenesis
  • testosterone stimulates development (in fetus) of male genitals/primary sexual
    characteristics
  • testosterone stimulates development of male secondary sexual characteristics

IB Biology 22-24 (13 decks)

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