Page 1:

• Neuron is the living nerve cell

  • Performs specific functions of the system

  • Transmits nerve impulses

• Neuron contains:

  • Cell body

    • Location of nucleus and other organelles

  • Protoplasmic processes

    • Dendrite

      • Conducts nerve impulses toward the cell body

    • Axon

      • Conducts nerve impulses away from the cell body

      • Covered by tightly packed Schwann cells

  • Terminal Node of Ranvier

  • Schwann cell myelin

  • Nucleus

Page 2:

• Types of neurons based on the number of protoplasmic processes:

  • Unipolar neuron

    • Location: Dorsal root ganglion of the spinal cord

  • Bipolar neuron

    • Location: Retina of the eye

  • Multipolar neuron

    • Location: Axon of the spinal cord

• Types of neurons based on functions:

  • Sensory neuron

    • Transmits impulses from sensory receptors to the nerve center (CNS)

  • Motor neuron

    • Transmits impulses from the nerve center to effectors (muscles or glands)

  • Associative neuron

    • Connects sensory and motor neurons

Page 3:

• Neuroglia

  • Actively dividing cells supporting the neurons of the nervous tissue

• Types of neuroglia based on function:

  • Astrocytes

    • Connect neurons and capillaries

  • Microglia

    • Dispose of dead cells, bacteria, etc.

  • Ependymal cells

    • Line the fluid-filled cavities of the CNS for protection

  • Oligodendrocytes

    • Form the myelin sheath around the fibers

  • Schwann cells and satellite cells

• Neuroglial cell types and function:

  • Astrocytes, ependymal cells, oligodendrocytes, microglia, satellite cells, and Schwann cells

  • Maintain blood-brain barrier, myelinate CNS neurons, provide support, regulate ion levels, remove neurotransmitters, etc.

Page 4:

• Peripheral Nervous System

  • Spinal nerves

    • Arise from the spinal cord

    • Dorsal and ventral roots connect spinal nerves to the spinal cord

    • Dorsal roots have ganglia

    • Spinal nerves through ramus communicans

      • Branches of spinal nerves

    • Dorsal ramus

      • Supplies epaxial muscles and skin (dorsal part)

    • Ventral ramus

      • Supplies hypaxial muscles and skin (ventral part)

• Gray and white matter in the spinal cord

• Dorsal root ganglion, spinal cord, sympathetic trunk, lateral horn, etc.

Page 5:

• Functional types of neurons in spinal nerves:

  • Somatic afferent

    • Sensory from general cutaneous receptors and proprioceptors

  • Somatic efferent

    • Motor to skeletal muscles

  • Visceral afferent

    • Sensory from receptors in the viscera

  • Visceral efferent

    • Motor to smooth, cardiac muscles, and glands

• Evolution of spinal nerves in different organisms

  • Amphioxus, hagfish, amniotes, fish, and amphibians

  • Dorsal and ventral nerves of each body segment

  • Different kinds of fibers outside the vertebral column

  • Somatic and visceral spinal nerves

Page 6:

• Cranial nerves

  • Classified into three general categories

  • Terminal nerve, olfactory, optic, oculomotor, trochlear, trigeminal, abducent, facial, vestibuloacoustic, glossopharyngeal, vagus, spinal accessory, hypoglossal

  • Serve structures in the head (nose, eye, ear, lateral line system)

  • Supply branchiometric muscles, sensory fibers, etc.

Page 7:

• Central Nervous System

  • Spinal cord differentiation in different organisms

  • Neural folds, gray and white matter, dorsal and ventral median sulcus and fissure

  • Cyclostomes, fishes and amphibians, reptiles and birds, mammals

Page 8:

• Development Structure and Evolution

  • Roof plate

    • Located in vertebral canal

    • Anatomical beginning is the foramen magnum of the skull.

  • Marginal layer

    • Length varies.

  • Alar plate

    • WITH TAIL - it extends to the caudal end of the vertebral column.

  • Basal plate

    • WITHOUT TAIL - it extends to about the lumbar region of the vertebral column.

  • Neural Tube: Cell Growth and Differentiation

    • Week 4

    • Floor plate

    • Spinal Cord

      • Gray matter - nerve cell bodies.

      • White matter - nerve cell processes.

    • Brain Development

      • SECONDARY VESICLES

        • Olfactory tracts

        • Cerebral hemispheres

      • PRIMARY VESICLES

        • Telencephalon

        • Diencephalon

        • Mesencephalon

        • Metencephalon

        • Myelencephalon

Page 9:

• VENTRICLE

  • 1st and 2nd ventricle (Lateral ventricles)

    • Occupies the cerebral hemispheres.

    • In Fishes with partly joined hemispheres, shared a common ventricle.

  • 3rd ventricle

    • In the diencephalons.

    • In mammals, tube-like neural canal which expands within the mesencephalon is called the AQUEDUCT.

  • 4th ventricle

    • Metencephalon and the Mylencephalon.

• Interventricular Feramen

• Third Ventricle

• Fourth Aqueduct

• Medulla oblangata

• METENCEPHALON

  • Pons and Cerebellum

• Tegmentum

• Tectum

• MESENCEPHALON

  • Tectum

  • Tegmentum

Page 10:

• Epithalamus

• Midbrain

• LOWER VERTEBRATES

  • Cerebral Epithalamus

  • Thalamus

• HIGHER VERTEBRATES

  • Thalamus

  • Hypothalamus

• Cerebellum

• Cerebrum

• Septum

• Striatum or basal ganglia

• Fish Amphibian Reptile Bird in complex Mammal movements

• Figure 15.2 BRAINS OF REPRESENTATIVE VERTEBRATES

  • Olfactory lobes

  • Cerebrum

  • Optic lobe

  • Cerebellum

  • Medulla

• Accessory Structures

  • Meninges

    • Pia mater

    • Arachnoid mater

    • Dura mater

  • Cerebrospinal Fluid

  • Blood-brain barrier

Page 11:

• Endocrine System of Vertebrates

Page 12:

• Endocrine System

  • Endocrine System consists of ductless glands that release hormones that are transported throughout the body by blood vessels.

  • Endocrine glands secrete chemical compounds called hormones into the blood system.

  • Hormones are secreted from a secretory cell in a gland and act on a target cell at another part of the body.

  • Target cells must have receptors for the specific hormone.

Page 13:

• Endocrine System Functions

  • Metabolism and tissue maturation

  • Ion regulation

  • Water balance

  • Immune system regulation

  • Heart rate and blood pressure regulation

  • Control of blood glucose and other nutrients

  • Control of reproductive functions

  • Uterine contractions and milk release

Page 14:

• MECHANISMS OF HORMONE SECRETION

  • Humoral Trigger

  • Neuronal Trigger

  • Hormonal Trigger

• Endocrine action

• Paracrine action

• Autocrine action

Page 15:

• Blood vessel Response

• Endocrine signaling Response

• Paracrine signaling - short distances

• Autocrine signaling - short distances

• Synapse Neuron Response

• Synaptic signaling Neurosecretory cell Blood vessel Response

• Neuroendocrine signaling

Page 16:

• Hypothalamus

• Pituitary gland

• Ovaries

• Pineal gland

• Thyroid gland

• Parathyroid glands

• Heart

• Adrenal gland

• Female Kidney

• Testes

• Stomach

• Pancreas

• Male Intestines

• The Endocrine System

Page 17:

• Hypothalamus

  • Located at the base of the brain

  • Controls the endocrine system by controlling the pituitary gland.

  • Secretes releasing hormones to cause the pituitary to release hormones.

  • Secretes inhibiting hormones to turn off secretion of pituitary hormones.

Page 18:

• Hypothalamus

• TSH-RH

• Pituitary

• TSH

• Thyroid gland

• TH

Page 19:

• Hypothalamus Regulation

• Thyroid Stimulating Hormone Releasing Hormone (TSH-RH)

• Thyroid Stimulating Hormone Inhibiting Hormone (TSH-IH)

Page 20:

• Hypothalamus Hormones

  • Growth Hormone Releasing Hormone (GH-RH)

  • Prolactin Releasing Hormone (PRL-RH)

  • Thyroid Stimulating Hormone Releasing Hormone (TSH-RH)

  • Adrenocorticotropic Hormone Releasing Hormone (ACTH- RH)

  • Melanocyte Stimulating Hormone Releasing Hormone (MSH-RH)

  • Follicle Stimulating Hormone Releasing Hormone (FSH-RH)

  • Luteinizing Hormone Releasing Hormone (LH-RH)

Page 21:

• Hypothalamus Hormones

  • Growth Hormone Inhibiting Hormone (GH-IH)

  • Prolactin Inhibiting Hormone (PRL-IH)

  • Thyroid Stimulating Hormone Inhibiting Hormone (TSH-IH)

  • Adrenocorticotropic Hormone Inhibiting Hormone (ACTH- IH)

  • Melanocyte Stimulating Hormone Inhibiting Hormone (MSH-IH)

  • Follicle Stimulating Hormone Inhibiting Hormone (FSH-IH)

  • Luteinizing Hormone Inhibiting Hormone (LH-IH)

Page 22:

• Pineal gland, Pituitary Gland, Hypothalamus

  • Secretes nine major hormones

  • Attached to the hypothalamus by the infundibulum (stalk)

• Two basic divisions of the pituitary gland

  • Hypothalamus - Adenohypophysis (anterior lobe)

  • Infundibulum

  • Anterior - Neurohypophysis (posterior lobe)

• Pituitary gland

• Posterior pituitary

• Spinal cord

Page 23:

• Hormones secreted by the anterior pituitary gland

  • Growth Hormone (GH)

  • Melanocyte stimulating hormone (MSH)

  • Adrenal corticotropic Hormone (ACTH)

  • Prolactin (PRL)

  • Thyroid stimulating hormone (TSH)

  • Luteinizing Hormone (LH)

  • Follicle stimulating Hormone (FSH)

Page 24:

• Growth Hormone (Somatotropin)

  • Travels through the blood and stimulates the liver to produce insulin-like growth factor (IGF-1)

  • In children, stimulates chondrocytes to multiply in the cartilage at the ends of long bones, leading to growth in height

  • In adults, plays a role in repair and maintenance of body tissues

  • IGF-1 also acts on immature muscle cells to increase muscle mass

Page 25:

• Hypersecretion of GH in children (Gigantism)

• Hypersecretion of GH in adults (Acromegaly)

• Hyposecretion of GH (dwarfism)

Page 26:

• Prolactin (PRL)

  • Stimulates lacrimation (desire to cry)

  • Enlarges mammary glands and stimulates milk production

  • Hypersecretion - overproduction of milk and enlargement of breasts

  • Hyposcretion - underproduction or no production of milk

Page 27:

• The Thyroid Gland

  • Located in the anterior neck, inferior to thyroid cartilage

Page 28:

• The Thyroid Gland

  • Thyroid Stimulating Hormone (TSH)

  • Produces two hormones: Thyroid hormone (TH) and Calcitonin

Page 29:

• The Thyroid Gland

  • Thyroid hormone (TH)

    • Acts on most cells of the body

    • Increases metabolic rate

    • Controlled by hormonal mechanism

    • Iodine is needed to make TH

  • Calcitonin

    • Lowers blood calcium levels

    • Slows osteoclasts to allow osteoblasts to deposit bone in the skeleton

Page 30:

• Melanocyte Stimulating Hormone (MSH)

  • Stimulates production and release of melanin by melanocytes in skin

  • Hypersecretion - unnaturally dark skin

  • Hyposecretion - prone to sunburn

Page 31:

• Adrenal corticotropic Hormone (ACTH)

  • Regulates the activity of the outer region (cortex) of the adrenal glands

Page 32:

• Adrenal Glands

  • Located on top of kidneys

  • Adrenal cortex

  • Adrenal medulla

  • Epinephrine - secreted mainly by the medulla of the adrenal glands, increases cardiac output

  • Norepinephrine - neurotransmitter and hormone, part of the fight-or-flight response, raises heart rate and releases glucose as energy

Page 33:

• Adrenal Glands

  • Adrenal cortex

    • Synthesizes and secretes corticosteroids as directed by ACTH

    • Mineralocorticoids affect salt and water balance

    • Glucocorticoids promote glucose synthesis

    • Androgens and Estrogens (male and female sex hormones)

  • Adrenal medulla

    • Epinephrine and Norepinephrine

Page 34:

• Gonadotropins

  • FSH and LH act on the gonads and regulate reproductive function

  • FSH regulates development of ovarian follicles and secretion of estrogen, and production of sperm in men

  • LH induces ovulation in females, induces testosterone in males, and stimulates ovulation and formation of the corpus luteum

Page 35:

• The Gonads

  • Ovaries

    • Progesterone prepares the endometrium for implantation and pregnancy

    • Estrogen matures the ovum and responsible for secondary female characteristics

  • Testes

    • Testosterone regulates production and maturation of sperm, responsible for secondary male sexual characteristics

Page 36:

• The Posterior Pituitary Hormones (The Neurohypophysis)

  • Oxytocin regulates release of milk in lactating women, induces uterine contractions in labor, and has a role in orgasm and inducing 'pair bonding'

  • Vasopressin (ADH) regulates body fluids, increases water reabsorption

Page 37:

• Parathyroid Glands

  • Four glands embedded on the posterior surface of the thyroid gland

  • Parathyroid hormone (PTH) increases blood concentration of calcium

  • Stimulates osteoclasts, stops kidneys from excreting calcium, and stimulates intestines to absorb more calcium from diet

  • Activates vitamin D which increases calcium uptake

  • Hypersecretion - softened bones from lack of calcium

  • Hyposecretion - low blood calcium levels

Page 39:

• Thymus Gland

  • Located in the thoracic cavity posterior to the sternum

  • Functions as part of the immune response and the endocrine system

  • Secretes thymosin involved in the activation of T lymphocytes (T-cells)

  • Hyposecretion - increased susceptibility to disease

Page 40:

• The Pineal Hormones

  • Pineal Gland located between the two lobes of the thalamus

  • Secretes the hormone melatonin

  • Maintains the body's internal clock and regulates the onset and duration of sleep

  • Stimulated by darkness and inhibited by light

Page 41:

• Fish endocrine system

  • Fish have ultimobranchial glands that secrete calcitonin

Page 42:

• Fish endocrine system

  • Corpuscles of Stannius are present in fish and produce the hormone stanniocalcin

  • Stanniocalcin decreases the blood circulating level of calcium

Page 43:

• Urophysis (Caudal neurosecretory System)

  • Hormones called "urotensins" are produced by the urophysis

  • Urotensin I increases blood pressure

  • Urotensin II is involved in the contraction of smooth muscles

  • Urotensin III induces sodium intake across the gills

  • Urotensin IV shows activity like antidiuretic hormones

Page 44:

• List of endocrine glands in birds

  • Pituitary gland

  • Hypothalamus

  • Pineal gland

  • Thyroid gland

  • Adrenal gland

  • Parathyroid glands

  • Gonad

  • Ultimobranchial glands

  • Kidney

  • Heart

  • Bursa of Fabriclus

  • Cloaca

  • Pancreas

  • Duodenum

Page 45:

• List of endocrine glands in humans

  • Pituitary gland

  • Suprarenal gland

  • Parotid gland

  • Brain

  • Ovaries (in females)

  • Pineal gland

  • Prostate (in males)

  • Placenta (in females)

  • Parathyroid

  • Thyroid

  • Pancreas

  • Gall

  • Mammary (in females)

  • Red bone marrow

  • Testes (orchic)

  • Liver (males)

Page 46:

• Table of major human endocrine glands and their hormones

  • Hypothalamus

    • Hormones released from the posterior pituitary and hormones that regulate the anterior pituitary

  • Posterior pituitary

    • Oxytocin: Stimulates contraction of uterus and mammary gland cells

    • Antidiuretic hormone (ADH): Promotes retention of water by kidneys

  • Anterior pituitary

    • Growth hormone (GH): Stimulates growth and metabolic functions

    • Prolactin: Stimulates milk production and secretion

    • Follicle-stimulating hormone (FSH): Stimulates production of ova and sperm

    • Luteinizing hormone (LH): Stimulates ovaries and testes

  • Thyroid gland

    • Triiodothyronine (T3) and thyroxine (T4): Stimulate and maintain metabolic processes

    • Calcitonin: Lowers blood calcium level

  • Parathyroid glands

    • Parathyroid hormone (PTH): Raises blood calcium level

Page 47:

• Table of major human endocrine glands and their hormones (continued)

  • Pancreas

    • Insulin: Lowers blood glucose level

    • Glucagon: Raises blood glucose level

  • Adrenal glands

    • Adrenal medulla

      • Epinephrine and norepinephrine: Raise blood glucose level, increase metabolic activities, constrict certain blood vessels

    • Adrenal cortex

      • Glucocorticoids: Raise blood glucose level

      • Mineralocorticoids: Promote reabsorption of Na+ and excretion of K+ in kidneys

  • Gonads

    • Testes

      • Androgens: Support sperm formation, promote development and maintenance of male secondary sex characteristics

    • Ovaries

      • Estrogens: Stimulate uterine lining growth, promote development and maintenance of female secondary sex characteristics

      • Progestins: Promote uterine lining growth

  • Pineal gland

    • Melatonin: Involved in biological rhythms

Page 48:

• List of hormones and their actions

  • T3 and T4: Increases metabolism

  • Cortisol: Increases blood glucose (stored glycogen converted to glucose)

  • Glucagon: Increases blood glucose

  • Epinephrine: Increases blood glucose

  • Insulin: Decreases blood glucose (glucose converted to stored glycogen)

  • Parathyroid hormone: Increases blood calcium level

  • Calcitonin: Decreases blood calcium level

  • Aldosterone: More sodium reabsorbed from kidney tubules

Page 49:

• Reproductive system in vertebrates

  • Gonads produce gametes and hormones

  • Associated ducts and glands store and transport gametes and secrete necessary substances

  • Most vertebrates have a cloaca, a common terminal chamber for the digestive, urinary, and reproductive tracts

  • Lampreys and most ray-finned fishes have a separate external opening for the alimentary canal (anus)

  • In reptiles and birds, the cloaca is partitioned into a urinogenital chamber and an alimentary chamber

  • Gonads arise as longitudinal thickenings of the coelomic epithelium and underlying mesenchyme

  • Gonadal ridges give rise to primary sex cords and establish a potentially male component (medulla) and a cortex

  • Differentiation of medullary or cortical component determines if the gonad becomes a testis or an ovary

Page 50:

• Length of adult gonad depends on the extent of gonadal-ridge differentiation

• Differentiation varies among different vertebrate groups

• Some species have only one gonad, either in the midline or on one side

• Birds typically have one ovary, while male birds have a pair of testes

• Exceptions to single ovaries among birds include some hawks and other species

• Some teleosts and viviparous elasmobranchs have only one ovary

• Unpaired gonads are unusual in amniotes, but some lizards and female crocodiles may have one gonad

• Platypus usually has only a left ovary, and some bat species have only the right

Page 51:

• Unpaired gonads can be explained by two possibilities:

  • Paired embryonic gonadal ridges fuse to form a median gonad (lampreys and perch).

  • Only one gonadal ridge receives primordial germ cells, resulting in the opposite gonad not developing (chickens and ducks).

• Hawks have an equal number of primordial germ cells in both gonadal ridges, resulting in two ovaries.

• Hermaphroditism is more common in cyclostomes and teleosts than in other fishes.

• Teleosts can function as males during the early part of their sexual life and as females later.

• Cyclostomes are generally ambisexual during juvenile life, with immature male and female sex cells existing side by side.

• Amphibians rarely exhibit hermaphroditism, although it can occur as an anomaly.

• True hermaphroditism is unlikely to exist in vertebrates above amphibians.

• In cyclostomes, elasmobranchs, and some teleosts, gametes are propelled towards the posterior within the coelom and exit via genital pores near the base of the tail.

Supporting details:

• Lampreys and perch have fused gonadal ridges to form a median gonad.

• Chickens and ducks have one gonadal ridge that does not develop.

• Hawks have an equal number of primordial germ cells in both gonadal ridges, resulting in two ovaries.

• Hermaphroditism is more common in cyclostomes and teleosts.

• Teleosts can function as males and females at different stages of their sexual life.

• Cyclostomes have immature male and female sex cells side by side.

• Amphibians rarely exhibit hermaphroditism, but it can occur as an anomaly.

• True hermaphroditism is unlikely to exist in vertebrates above amphibians.

• In cyclostomes, elasmobranchs, and some teleosts, gametes are propelled towards the posterior within the coelom and exit via genital pores near the base of the tail.

Page 52:

• Testes in anurans, amniotes, and some teleosts are composed mainly of seminiferous tubules.

• Seminiferous tubules can constitute up to 90 percent of the testis.

• The walls of seminiferous tubules contain cells that produce sperm and are surrounded by a capsule called the tunica albuginea.

• In frogs, seminiferous tubules may begin blindly at the outermost tissue layer and pass towards the center before emptying into the rete testis.

• In some mammals, the tubules may be open-ended and run a zigzag course from the rete to the periphery and back again.

• In many mammals, the tubules are grouped into lobules separated by connective tissue septa.

• The tubules are inconspicuous and inactive in immature males and adult males between breeding seasons.

• Spermatogenesis can occur at a variable pace throughout the year in some species.

• The lumen of the tubules contains developing sperm, free sperm, and fluid.

• Different zones along a tubule contain sperm at different stages of maturation.

Supporting details:

• Testes in anurans, amniotes, and some teleosts consist mainly of seminiferous tubules.

• Seminiferous tubules can make up to 90 percent of the testis.

• The walls of seminiferous tubules contain cells that produce sperm and are surrounded by the tunica albuginea.

• In frogs, seminiferous tubules begin blindly and pass towards the center before emptying into the rete testis.

• In some mammals, the tubules run a zigzag course from the rete to the periphery and back again.

• In many mammals, the tubules are grouped into lobules separated by connective tissue septa.

• The tubules are inactive in immature males and adult males between breeding seasons.

• Spermatogenesis can occur throughout the year in some species.

• The lumen of the tubules contains developing sperm, free sperm, and fluid.

• Different zones along a tubule contain sperm at different stages of maturation.

Page 53:

• In cyclostomes, most fishes, and tailed amphibians, the germinal epithelium is arranged differently.

• Instead of seminiferous tubules, there are spermatogonial cysts in which sperm develop.

• Spermatogenic cells migrate into the cysts from a permanent germinal layer.

• The cysts become swollen and whitish as sperm mature.

• The cysts burst, and the sperm are shed into ducts.

• In cyclostomes and some teleosts, the sperm are shed into the coelom.

• Testicular stroma consists of connective tissue, blood and lymphatic vessels, and nerves.

• Leydig cells, which produce male hormones, are present in most vertebrates.

Supporting details:

• In cyclostomes, most fishes, and tailed amphibians, the germinal epithelium is arranged differently.

• Spermatogonial cysts are present instead of seminiferous tubules.

• Spermatogenic cells migrate into the cysts from a permanent germinal layer.

• The cysts become swollen and whitish as sperm mature.

• The cysts burst, and the sperm are shed into ducts.

• In cyclostomes and some teleosts, the sperm are shed into the coelom.

• Testicular stroma consists of connective tissue, blood and lymphatic vessels, and nerves.

• Leydig cells, which produce male hormones, are present in most vertebrates.

Page 54:

• The male duct system begins with the rete testis, which collects sperm from the seminiferous tubules.

• The rete is drained by small ducts called vasa efferentia.

• In anamniotes, the ducts that drain the kidneys usually drain the testes as well.

• In some amphibians, the ducts pass posteriorly to empty into the cloaca.

• In some fishes, the ducts pass through a median urinogenital papilla.

• There is a tendency in many vertebrates towards separate spermatic and urinary ducts.

• Different patterns of duct separation occur in anamniotes.

Supporting details:

• The male duct system begins with the rete testis, which collects sperm from the seminiferous tubules.

• The rete is drained by small ducts called vasa efferentia.

• In anamniotes, the ducts that drain the kidneys usually drain the testes as well.

• In some amphibians, the ducts pass posteriorly to empty into the cloaca.

• In some fishes, the ducts pass through a median urinogenital papilla.

• There is a tendency in many vertebrates towards separate spermatic and urinary ducts.

• Different patterns of duct separation occur in anamniotes.

Page 55:

• Mesonephric kidney is temporary in amniotes

  • Mesonephric duct persists in adult males as sperm duct

  • Separate ureter drains adult kidney

• Epididymis serves as temporary storage place for sperm in amniotes

  • Small in birds, large in turtles

  • Consists of head, body, and tail in mammals

  • Secretes substances that prolong sperm life and increase motility

• Spermatic duct lined by cilia and secretory epithelial cells

  • Can form sperm reservoir or secrete seminal fluid

• Cloacal glands in some animals produce gelatinous plug or pheromones

• Siphon sac in elasmobranchs secretes nutritive mucus with sperm

Page 56:

• Accessory sex glands are mostly found in mammals

• Major mammalian sex glands include prostate, bulbourethral, ampullary glands, and seminal vesicles

• Prostate is widely distributed, absent in Echidna and some carnivores

• Bulbourethral glands are small in man, large in rodents and some ungulates

• Ampullary glands are present in some mammals, absent in others

• Seminal vesicles are elongated and coiled sacs, absent in some mammals

Page 57:

• Ovaries are suspended by mesovarium in body cavity

• Hagfish ovaries contain functional ovarian tissue in forward half, rudimentary testicular tissue in rear part

• Ovaries in fishes are elongated

• Ovaries in tetrapods are usually confined to middle third or half of body cavity

• Ovaries in mammals undergo caudal displacement, lie between kidney and pelvis

• Appearance of ovary depends on factors like ovulation, maturity of eggs, pigments in egg cytoplasm

• Ovaries covered with germinal epithelium, which may contain germ cells in some species

• Germinal epithelium undergoes cell division in species with large ovary expansion

• Beneath epithelium is tunica albuginea, thinner than that surrounding testes

Page 58:

• Ovaries in hagfishes and amphibians contain cells that give rise to eggs in germinal epithelium

• Germinal epithelium in most adults contains no germ cells

• Germinal epithelium undergoes cell division in species with large ovary expansion

• Beneath epithelium is tunica albuginea, thinner than that surrounding testes

Page 59:

• Structure of a typical vertebrate ovary

  • Cortex and medulla

  • Cortex contains future eggs, developing eggs, remnants of ovulated follicles, and interstitial cells

  • Medulla consists of blood and lymph vessels, nerves, and connective tissue

• Different types of ovaries in different species

  • Saccular, hollow, lacunate, or compact

  • Teleost ovaries may have permanent or temporary cavities

  • Amphibian ovaries have central hollow sacs

  • Reptiles, birds, and monotremes have cavities similar to amphibians

  • Mammalian ovaries above monotremes are compact

Page 60:

• Development of follicular epithelium

  • Originates from germinal epithelium

  • Primary follicles are under the tunica albuginea, secondary follicles are deeper in the cortex

• Role of follicular cells

  • Secretion of yolk-forming material onto or into the oocyte

  • Conversion of substances into female hormones

  • Glycogen storage in hibernating bats

• Formation of antrum in mammalian follicles

  • Fluid-filled cavity within the granulosa layer

  • Granulosa cell division and development of fluid-filled spaces

  • Pituitary gonadotropic hormones influence antral follicle growth

  • Graafian follicles contain mature eggs and appear as large blisters on the ovary

Page 61:

• Atresia or degeneration of oocytes

  • Normal process that reduces the number of eggs ovulated

  • Occurs until just before ovulation

• Anovular and polyovular follicles

  • Follicles lacking oocytes and antra

  • Follicles containing more than one oocyte

• Structure of ovarian follicle

  • Surrounded by a theca composed of stromal cells

  • Theca externa is connective tissue, theca interna has more blood vessels

  • Microvilli facilitate transport of substances for yolk formation

Page 62:

• Growth phase and vitellogenesis

  • Eggs with massive amounts of yolk increase in size significantly

  • Goldfish eggs increase in size during vitellogenesis

  • Mammalian eggs contain little yolk and vary little in size

• Size of oogonia and mature eggs in different species

  • Golden hamster oogonia are 15 microns in diameter, Graafian follicle eggs are 70 microns

  • Mature eggs of horses and humans are less than 150 microns

• Ovarian weight and development in different species

  • Seasonally breeding oviparous fishes and amphibians have all eggs in the same stage of development

  • Ovaries of reptiles and birds have high weight during egg-laying seasons

  • Ovarian weight to body weight ratio varies insignificantly in mammals

Page 63:

• Ovulation process in vertebrates

  • Elasmobranchs, reptiles, and birds have yolked eggs

  • Fimbria of the membranous and muscular funnel wave to draw the egg into the oviduct

  • Cilia help sweep eggs into the opening of the oviduct

  • Japanese rice fish: papilla develops on the surface of a mature follicle, egg rolls out

  • Rabbits: blood vessels rupture, blood forms under the papilla, follicular fluid oozes out followed by the egg

  • Mammalian egg surrounded by corona radiata, but naked in some insectivores and marsupials

  • Ovary may become smaller, modified for pregnancy, or form additional eggs

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• Immediate causes of ovulation not clarified

• Ovulatory hormone secreted by the pituitary gland in all vertebrates

• Fibres binding follicular cells may break down at the stigma, weakening the follicular wall

• Hormones from ovary and other sources, as well as neurohormones, may play a role

• Rhythmic contractions of the ovary occur at ovulation

• Spontaneous ovulation in most mammals, reflex ovulation in a few mammals

• Postovulatory changes in follicles result in the formation of corpora lutea in mammals

• Corpora lutea produce progesterone for pregnancy maintenance

• Similar changes observed in viviparous reptiles, amphibians, elasmobranchs, certain fishes, and some oviparous amphibians and reptiles

• Birds: postovulatory follicle shrinks, no identifiable corpora lutea develop

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• Female reproductive tract consists of gonoducts

• Gonoducts specialized for secretion, transport, storage, nutrition, and expulsion of eggs or products of conception

• Gonoducts lined by secretory epithelium and ciliated

• Fusion of caudal ends of ducts may occur

• Gonoducts absent in cyclostomes and some gnathostome fishes

• Lungfishes and amphibians have coiled muscular tubes that are ciliated

• Anurans have expanded lower end of gonoduct forming ovisac for storing ovulated eggs

• Amphibians have multicellular glands in the female tract

• Female urodeles have spermatheca for storing sperm

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• Elasmobranchs have two gonoducts sharing a single ostium

• Oviducts pass forward from ostium to septum transversum, curve around liver, then pass posteriorly

• Shell gland secretes albumen and shell

• Viviparous shark Squalus acanthias has one long delicate membranous shell for multiple eggs

• Oviducts terminate in uterus, may have oviducal valve

• Uteri usually open independently into cloaca, occasionally unite to form bicornuate structure

• Hymen may separate uterus from cloaca in immature females

• Gonoducts of most lower ray-finned fishes resemble those of lungfish

• Gars and teleosts have oviducts continuous with ovarian cavities

• Teleosts have median genital papilla and elongated ovipositor in some cases

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• Reptiles and birds have comparable gonoducts to lower vertebrates

  • Crocodilians, some lizards, and nearly all birds have one well-developed gonoduct

  • The other gonoduct is not well developed

  • Birds of prey with two functional ovaries sometimes have an undeveloped right oviduct

• Reptiles have less regional differentiation in their reproductive tracts compared to birds

• The oviduct funnel in birds forms the chalazae, which are coiled cords extending from the yolk to the ends of the egg

• The female tract in reptiles and birds is mostly oviduct

• The magnum in birds secretes albumen, while lizards and snakes do not form albumen

• In lizards, the shell gland is midway along the tract, while in birds, it is at the posterior end and is often called a uterus

• The isthmus in birds secretes the noncalcareous membranes of the shell

• The shell gland leads to a narrow muscular vagina that empties into the cloaca

• The vagina in birds secretes mucus that seals the pores of the shell before the egg is expelled

• Some snakes and lizards have special vaginal tubules (spermatheca) for storing sperm over winter

• Birds have sperm storage glands (sperm nests) in the oviduct funnel and at the uterovaginal junction

• Ovulation in lizards and birds usually does not occur into a tract already containing an egg

• Monotremes have two oviducts that open into a urinogenital sinus, which empties into a cloaca

• Marsupials have two oviducts, two uteri, and two vaginas

• The upper parts of the vaginas in marsupials unite to form a median vagina, which may or may not be paired internally

• The lateral vaginas in marsupials receive the forked tips of the male penis

• Fertilization in all mammals takes place in the oviducts

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• Eutherian mammals (all mammals except monotremes and marsupials) have two narrow and tortuous Fallopian tubes, two large uterine horns, a uterine body, and one vagina

• Fallopian tubes often have a short dilated ampulla beyond the ostium

• Implantation of the egg occurs only in the uterine horns

• In some species, one uterine horn is rudimentary, and the embryos become implanted in the other horn

• The body of the uterus in some mammals contains two separate canals (bipartite uterus), while in others, it has one chamber into which the two horns empty (bicornuate uterus)

• Apes, monkeys, and humans have no horns, and the Fallopian tubes empty directly into the body of the uterus (simplex uterus)

• The uterine body tapers to a narrow neck (cervix) and opens into the vagina through the os uteri

• The vagina in eutherian mammals terminates in a urinogenital sinus, except in rodents and higher primates where it opens directly to the exterior

• In many species, a membrane called the hymen closes the vaginal opening in the young

• Female mammals have fewer accessory sex glands than males, including Bartholin's glands and prostates

• Bartholin's glands are homologues of the bulbourethral glands in males and usually open into the urinogenital sinus or a shallow vestibule in primates

• Prostates develop as buds from the urethra in female embryos but often remain partially developed

• Various glands (labial, preputial, urethral) are found in the mucosa of the reproductive tract

• Uterine mucosa glands provide nourishment for embryos before implantation

• Cervical uterine glands