Anatomy & Physiology II: The Male Reproductive System

Sustentacular Cells: - Also called _______ cells - _______ (stem) cell and its _______ cells are surrounded by sustentacular cells for support - They deliver _______ to cells - They assist in moving the _______ cells to the _______ - They secret _______ fluid a.) Rich in _______ b.) Is a transport medium for _______

Sustentacular Cells: - Also called sertoli cells - Spermatogonium (stem) cell and its daughter cells are surrounded by sustentacular cells for support - They deliver nutrients to cells - They assist in moving the daughter cells to the lumen - They secret testicular fluid a.) Rich in androgens b.) Is a transport medium for sperm

Hormonal Regulation: 1. The _______ releases Gonadotropin-Releasing Hormone (GnRH) a.) GnRH reaches the _______ _______ cells via the hypophyseal portal system b.) GnRH controls release of _______ Stimulating Hormone (FSH) and _______ Hormone (LH) 2. GnRH binds to pituitary _______ cells and tells them to secrete ____ and ____ into the blood 3. FSH tells _______ to release _______-Binding Protein (ABP), which keeps the concentration of _______ high a.) Purpose is to stimulate _______ 4. LH binds to the _______ _______ cells found in seminiferous tubules and tells them to secrete _______ (and small amounts of _______) a.) The rise in _______ serves as the final trigger for _______ 5. Rising testosterone levels feed back to _______ the hypothalamus from releasing more _______ and act directly on the anterior pituitary to inhibit _______ release 6. _______, a protein hormone made by sustentocytes serves as a _______ for spermatogenesis. a.) When the sperm count is _______, more inhibin is released to make sure hypothalamus stop releasing GnRh and anterior pituitary stops releasing FSH b.) When the sperm count falls below ____ million, secretion steeply _______

Hormonal Regulation: 1. The hypothalamus releases Gonadotropin-Releasing Hormone (GnRH) a.) GnRH reaches the anterior pituitary cells via the hypophyseal portal system b.) GnRH controls release of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) 2. GnRH binds to pituitary gonadotropic cells and tells them to secrete FSH and LH into the blood 3. FSH tells sustentocytes to release Androgen-Binding Protein (ABP), which keeps the concentration of Testosterone high a.) Purpose is to stimulate spermatogenesis 4. LH binds to the interstitial endocrine cells found in seminiferous tubules and tells them to secrete testosterone (and small amounts of estrogens) a.) The rise in testosterone serves as the final trigger for spermatogenesis 5. Rising testosterone levels feed back to inhibit the hypothalamus from releasing more GnRH and act directly on the anterior pituitary to inhibit gonadotropin release 6. Inhibin, a protein hormone made by sustentocytes serves as a barometer for spermatogenesis. a.) When the sperm count is high, more inhibin is released to make sure hypothalamus stop releasing GnRh and anterior pituitary stops releasing FSH b.) When the sperm count falls below 20 million, secretion steeply declines

Oogenesis: Follicle Development in Ovary 1. Primordial follicle is activated and becomes a _______ follicle when squamous-like cells surrounding the primary _______ grow and become _______ cells and the oocyte _______ 2. The follicular cells proliferate, forming a stratified epithelium around the oocyte, it is now a _______ follicle 3. The secondary follicle stage ends when a clear liquid begins to accumulate between _______ cells a.) Now called an _______ _______ follicle 4. It becomes a _______ _______ follicle when the oocyte sitting on a stalk on one side of the follicle 5. The _______ bulges fro the external ovarian surface like a boil a.) This occurs right before _______ 6. When the follicle _______, the secondary oocyte is ovulated 7. In absence of _______, the ruptured follicle becomes a _______ _______ and ultimately _______ a.) Corpus luteum continues to produce _______ for 10 days

Oogenesis: Follicle Development in Ovary 1. Primordial follicle is activated and becomes a primary follicle when squamous-like cells surrounding the primary oocyte grow and become cuboidal cells and the oocyte enlarges 2. The follicular cells proliferate, forming a stratified epithelium around the oocyte, it is now a secondary follicle 3. The secondary follicle stage ends when a clear liquid begins to accumulate between granulosa cells a.) Now called an early vesicular follicle 4. It becomes a late vesicular follicle when the oocyte sitting on a stalk on one side of the follicle 5. The oocyte bulges fro the external ovarian surface like a boil a.) This occurs right before ovulation 6. When the follicle ruptures, the secondary oocyte is ovulated 7. In absence of fertilization, the ruptured follicle becomes a corpus luteum and ultimately degenerates a.) Corpus luteum continues to produce estrogen for 10 days

Oogenesis: Meiotic Events 1. A single _______ (stem cell) from the ovary multiplies rapidly when it undergoes mitosis a.) Oogonium transforms into a _______ oocyte b.) _______ follicle appear at this time 2. The primary oocyte begins the first _______ division, but become "stalled" late in _______ and do not complete it because the female has not yet gone through _______ 3. At the beginning of puberty, a _______ primary oocyte continues meiosis each _______ in response to an ____ _______ 4. Primary oocyte now divides and turns into one _______ oocyte and a smaller, less developed cell called the _______ _______ _______ 5. The secondary oocyte is "stalled" in _______ a.) Meiosis II of the _______ _______ may or may not occur 6. Meiosis II is completed only if the _______ penetrates the oocyte a.) The fertilized egg is now called an _______ b.) In this case, the ruptured _______ _______ will continue to secrete estrogen for ____ months

Oogenesis: Meiotic Events 1. A single oogonium (stem cell) from the ovary multiplies rapidly when it undergoes mitosis a.) Oogonium transforms into a primary oocyte b.) Primordial follicle appear at this time 2. The primary oocyte begins the first meiotic division, but become "stalled" late in prophase I and do not complete it because the female has not yet gone through puberty 3. At the beginning of puberty, a single primary oocyte continues meiosis each month in response to an LH surge 4. Primary oocyte now divides and turns into one secondary oocyte and a smaller, less developed cell called the first polar body 5. The secondary oocyte is "stalled" in metaphase II a.) Meiosis II of the polar body may or may not occur 6. Meiosis II is completed only if the sperm penetrates the oocyte a.) The fertilized egg is now called an Ovum b.) In this case, the ruptured corpus luteum will continue to secrete estrogen for 3 months

Sperm Entrance into the Oocyte: 1. The sperm weaves past the _______ cells of the _______ _______ a.) _______ enzymes help this happen 2. The sperm binds to ____ molecules in the _______ _______ a.) This causes a rise in ____ levels in the _______, which triggers the _______ reaction 3. _______ enzymes digest holes through the zona pellucida a.) This clears a path to the _______ membrane 4. The sperm forms an _______ process that binds to the oocyte's sperm-binding _______ 5. The sperm and oocyte plasma membranes _______, which allows the _______ contents to enter the _______ 6. The entry of sperm contents causes a rise in Ca2+ levels in the _______ cytoplasm a.) The Ca2+ rise triggers the _______ reaction, which is the _______ of _______ granules 7. The removal of the _______ granules causes the zona pellucida to _______ and their sperm receptors are _______ _______ a.) This avoids _______, which is when 2 sperm cells (____ chromosomes) enter 1 oocyte b.) _______ = Non-viable cell

Sperm Entrance into the Oocyte: 1. The sperm weaves past the granulosa cells of the corona radiata a.) Hyaluronidase enzymes help this happen 2. The sperm binds to ZP3 molecules in the zona pellucida a.) This causes a rise in Ca2+ levels in the sperm, which triggers the acrosomal reaction 3. Acrosomal enzymes digest holes through the zona pellucida a.) This clears a path to the oocyte membrane 4. The sperm forms an acrosomal process that binds to the oocyte's sperm-binding receptors 5. The sperm and oocyte plasma membranes fuse, which allows the sperm contents to enter the oocyte 6. The entry of sperm contents causes a rise in Ca2+ levels in the oocyte's cytoplasm a.) The Ca2+ rise triggers the cortical reaction, which is the exocytosis of cortical granules 7. The removal of the cortical granules causes the zona pellucida to harden and their sperm receptors are clipped off a.) This avoids polyspermy, which is when 2 sperm cells (69 chromosomes) enter 1 oocyte b.) Polyspermy = Non-viable cell

Spermatogenesis: - Production of the _______/_______ - ____ million per day - 2 Phases: 1. _______ (early spermatogenesis) 2. _______ (late spermatogenesis) - Occurs _______ the systentacular cells found in _______ _______ - Takes ____-____days - Sperm in the _______ of seminiferous tubules are immature and unable to _______ yet a.) They will mature in the _______

Spermatogenesis: - Production of the gametes/sperm - 400 million per day - 2 Phases: 1. Meiosis (early spermatogenesis) 2. Spermiogenesis (late spermatogenesis) - Occurs between the systentacular cells found in seminiferous tubules - Takes 64-72 days - Sperm in the lumen of seminiferous tubules are immature and unable to swim yet a.) They will mature in the epididymis

Spermatogenesis: 1. _______ produces 2 daughter cells a.) Type A remains a _______ cell b.) Type B starts the _______ I process by developing into a _______ _______ 2. The primary spermatocyte divides into 2 _______ spermatocytes a.) This _______ meiosis I 3. Meiosis II begins when the 2 secondary spermatocytes divide into 4 _______ _______ a.) Spermatids are _______ cells 4. The early spermatids turn into _______ _______ when they grow a tail and head a.) This completes the ____ phase of spermatogenesis b.) Beginning of _______ (phase 2) 5. Late spermatids develop into _______ (developed sperm cell)

Spermatogenesis: 1. Spermatogonium produces 2 daughter cells a.) Type A remains a stem cell b.) Type B starts the meiosis I process by developing into a primary spermatocyte 2. The primary spermatocyte divides into 2 secondary spermatocytes a.) This completes meiosis I 3. Meiosis II begins when the 2 secondary spermatocytes divide into 4 early spermatids a.) Spermatids are haploid cells 4. The early spermatids turn into late spermatids when they grow a tail and head a.) This completes the 1st phase of spermatogenesis b.) Beginning of spermiogenesis (phase 2) 5. Late spermatids develop into spermatozoa (developed sperm cell)

Spermatogenesis: Meiosis (Early Spermatogenesis) - Cell replication that _______ chromosomal count by _______ - Occurs only in the _______ - Stem cells in the _______ _______ are divided by mitosis: a.) No _______ reduction b.) All stem cells have ____ chromosomes (____ pairs) c.) Chromosomes _______ just before cells _______ - The stem cells are called _______ a.) Divide by mitosis until _______ hits b.) At puberty, _______ occurs and spermatogonia are divided _______ - Spermatogonia produce 2 daughter cells: 1. Type A: Remains a stem cell (_______) 2. Type B: Moves towards the _______ and becomes a _______ spermatocyte

Spermatogenesis: Meiosis (Early Spermatogenesis) - Cell replication that reduces chromosomal count by half - Occurs only in the gonads - Stem cells in the seminiferous tubules are divided by mitosis: a.) No chromosome reduction b.) All stem cells have 46 chromosomes (23 pairs) c.) Chromosomes duplicate just before cells divide - The stem cells are called spermatogonia a.) Divide by mitosis until puberty hits b.) At puberty, spermatogenesis occurs and spermatogonia are divided mitotically - Spermatogonia produce 2 daughter cells: 1. Type A: Remains a stem cell (spermatogonia) 2. Type B: Moves towards the lumen and becomes a primary spermatocyte

Spermatogenesis: Spermatids to Sperm - Spermatids must be 'streamlined' a.) Process is called _______ - The excess _______ is shed off and a _______ is formed - Sperm (or _______) has 3 regions: 1. Head (_______) 2. Midpiece (_______) 3. Tail (_______) - During development, the freely moving mitochondria found in the cytoplasm eventually _______ the tail in the _______ when the cytoplasm is shed - The mid piece of the sperm cell holds _______ DNA, however we only inherit _______ DNA from our _______ - The head contains an ______ a.) Has _______ that break down the _______ cell

Spermatogenesis: Spermatids to Sperm - Spermatids must be 'streamlined' a.) Process is called spermiogenesis - The excess cytoplasm is shed off and a tail is formed - Sperm (or spermatozoon) has 3 regions: 1. Head (genes) 2. Midpiece (energy) 3. Tail (locomotion) - During development, the freely moving mitochondria found in the cytoplasm eventually lines the tail in the mid piece when the cytoplasm is shed - The mid piece of the sperm cell holds mitochondrial DNA, however we only inherit mitochondrial DNA from our mother - The head contains an acrozome a.) Has enzymes that break down the oocyte cell

Spermatogenesis: Vocabulary - _______/_______: Stem cell that develops 2 daughter cells - _______: The cell that the Type B daughter cell turns into after entering the lumen - _______: The 4 haploid cells that come from the secondary spermatocyte - _______: Developed sperm cell - _______: The overall production process of gametes/sperm - _______: Second phase of Spermatogenesis, when the late spermatids turn into spermatozoa

Spermatogenesis: Vocabulary - Spermatogonium/Spermatogonia: Stem cell that develops 2 daughter cells - Spermatocyte: The cell that the Type B daughter cell turns into after entering the lumen - Spermatids: The 4 haploid cells that come from the secondary spermatocyte - Spermatozoa: Developed sperm cell - Spermatogenesis: The overall production process of gametes/sperm - Spermiogenesis: Second phase of Spermatogenesis, when the late spermatids turn into spermatozoa